content/public/android/java/src/org/chromium/content/browser/accessibility/AccessibilityInjector.java - platform/external/chromium_org - Git at Google

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 package org.chromium.content.browser.accessibility;

 import android.accessibilityservice.AccessibilityServiceInfo;
 import android.content.Context;
 import android.content.pm.PackageManager;
 import android.os.Build;
 import android.os.Bundle;
 import android.os.Vibrator;
 import android.speech.tts.TextToSpeech;
 import android.util.Log;
 import android.view.View;
 import android.view.accessibility.AccessibilityManager;
 import android.view.accessibility.AccessibilityNodeInfo;

 import com.googlecode.eyesfree.braille.selfbraille.SelfBrailleClient;
 import com.googlecode.eyesfree.braille.selfbraille.WriteData;

 import org.apache.http.NameValuePair;
 import org.apache.http.client.utils.URLEncodedUtils;
 import org.chromium.base.CommandLine;
 import org.chromium.content.browser.ContentViewCore;
 import org.chromium.content.browser.JavascriptInterface;
 import org.chromium.content.browser.WebContentsObserver;
 import org.chromium.content.common.ContentSwitches;
 import org.json.JSONException;
 import org.json.JSONObject;

 import java.net.URI;
 import java.net.URISyntaxException;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;

 /**
  * Responsible for accessibility injection and management of a {@link ContentViewCore}.
  */
 public class AccessibilityInjector extends WebContentsObserver {
     private static final String TAG = "AccessibilityInjector";

     // The ContentView this injector is responsible for managing.
     protected ContentViewCore mContentViewCore;

     // The Java objects that are exposed to JavaScript
     private TextToSpeechWrapper mTextToSpeech;
     private VibratorWrapper mVibrator;
     private final boolean mHasVibratePermission;

     // Lazily loaded helper objects.
     private AccessibilityManager mAccessibilityManager;

     // Whether or not we should be injecting the script.
     protected boolean mInjectedScriptEnabled;
     protected boolean mScriptInjected;

     private final String mAccessibilityScreenReaderUrl;

     // To support building against the JELLY_BEAN and not JELLY_BEAN_MR1 SDK we need to add this
     // constant here.
     private static final int FEEDBACK_BRAILLE = 0x00000020;

     // constants for determining script injection strategy
     private static final int ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED = -1;
     private static final int ACCESSIBILITY_SCRIPT_INJECTION_OPTED_OUT = 0;
     private static final int ACCESSIBILITY_SCRIPT_INJECTION_PROVIDED = 1;
     private static final String ALIAS_ACCESSIBILITY_JS_INTERFACE = "accessibility";
     private static final String ALIAS_ACCESSIBILITY_JS_INTERFACE_2 = "accessibility2";

     // Template for JavaScript that injects a screen-reader.
     private static final String DEFAULT_ACCESSIBILITY_SCREEN_READER_URL =
             "https://ssl.gstatic.com/accessibility/javascript/android/chromeandroidvox.js";

     private static final String ACCESSIBILITY_SCREEN_READER_JAVASCRIPT_TEMPLATE =
             "(function() {"
             + "    var chooser = document.createElement('script');"
             + "    chooser.type = 'text/javascript';"
             + "    chooser.src = '%1s';"
             + "    document.getElementsByTagName('head')[0].appendChild(chooser);"
             + "  })();";

     // JavaScript call to turn ChromeVox on or off.
     private static final String TOGGLE_CHROME_VOX_JAVASCRIPT =
             "(function() {"
             + "    if (typeof cvox !== 'undefined') {"
             + "        cvox.ChromeVox.host.activateOrDeactivateChromeVox(%1s);"
             + "    }"
             + "  })();";

     /**
      * Returns an instance of the {@link AccessibilityInjector} based on the SDK version.
      * @param view The ContentViewCore that this AccessibilityInjector manages.
      * @return An instance of a {@link AccessibilityInjector}.
      */
     public static AccessibilityInjector newInstance(ContentViewCore view) {
         if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
             return new AccessibilityInjector(view);
         } else {
             return new JellyBeanAccessibilityInjector(view);
         }
     }

     /**
      * Creates an instance of the IceCreamSandwichAccessibilityInjector.
      * @param view The ContentViewCore that this AccessibilityInjector manages.
      */
     protected AccessibilityInjector(ContentViewCore view) {
         super(view.getWebContents());
         mContentViewCore = view;

         mAccessibilityScreenReaderUrl = CommandLine.getInstance().getSwitchValue(
                 ContentSwitches.ACCESSIBILITY_JAVASCRIPT_URL,
                 DEFAULT_ACCESSIBILITY_SCREEN_READER_URL);

         mHasVibratePermission = mContentViewCore.getContext().checkCallingOrSelfPermission(
                 android.Manifest.permission.VIBRATE) == PackageManager.PERMISSION_GRANTED;
     }

     /**
      * Injects a <script> tag into the current web site that pulls in the ChromeVox script for
      * accessibility support.  Only injects if accessibility is turned on by
      * {@link AccessibilityManager#isEnabled()}, accessibility script injection is turned on, and
      * javascript is enabled on this page.
      *
      * @see AccessibilityManager#isEnabled()
      */
     public void injectAccessibilityScriptIntoPage() {
         if (!accessibilityIsAvailable()) return;

         int axsParameterValue = getAxsUrlParameterValue();
         if (axsParameterValue != ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED) {
             return;
         }

         String js = getScreenReaderInjectingJs();
         if (mContentViewCore.isDeviceAccessibilityScriptInjectionEnabled()
                 && js != null && mContentViewCore.isAlive()) {
             addOrRemoveAccessibilityApisIfNecessary();
             mContentViewCore.getWebContents().evaluateJavaScript(js, null);
             mInjectedScriptEnabled = true;
             mScriptInjected = true;
         }
     }

     /**
      * Handles adding or removing accessibility related Java objects ({@link TextToSpeech} and
      * {@link Vibrator}) interfaces from Javascript.  This method should be called at a time when it
      * is safe to add or remove these interfaces, specifically when the {@link ContentViewCore} is
      * first initialized or right before the {@link ContentViewCore} is about to navigate to a URL
      * or reload.
      * <p>
      * If this method is called at other times, the interfaces might not be correctly removed,
      * meaning that Javascript can still access these Java objects that may have been already
      * shut down.
      */
     public void addOrRemoveAccessibilityApisIfNecessary() {
         if (accessibilityIsAvailable()) {
             addAccessibilityApis();
         } else {
             removeAccessibilityApis();
         }
     }

     /**
      * Checks whether or not touch to explore is enabled on the system.
      */
     public boolean accessibilityIsAvailable() {
         if (!getAccessibilityManager().isEnabled()
                 || mContentViewCore.getContentSettings() == null
                 || !mContentViewCore.getContentSettings().getJavaScriptEnabled()) {
             return false;
         }

         try {
             // Check that there is actually a service running that requires injecting this script.
             List<AccessibilityServiceInfo> services =
                     getAccessibilityManager().getEnabledAccessibilityServiceList(
                             FEEDBACK_BRAILLE | AccessibilityServiceInfo.FEEDBACK_SPOKEN);
             return services.size() > 0;
         } catch (NullPointerException e) {
             // getEnabledAccessibilityServiceList() can throw an NPE due to a bad
             // AccessibilityService.
             return false;
         }
     }

     /**
      * Sets whether or not the script is enabled.  If the script is disabled, we also stop any
      * we output that is occurring. If the script has not yet been injected, injects it.
      * @param enabled Whether or not to enable the script.
      */
     public void setScriptEnabled(boolean enabled) {
         if (enabled && !mScriptInjected) injectAccessibilityScriptIntoPage();
         if (!accessibilityIsAvailable() || mInjectedScriptEnabled == enabled) return;

         mInjectedScriptEnabled = enabled;
         if (mContentViewCore.isAlive()) {
             String js = String.format(TOGGLE_CHROME_VOX_JAVASCRIPT, Boolean.toString(
                     mInjectedScriptEnabled));
             mContentViewCore.getWebContents().evaluateJavaScript(js, null);

             if (!mInjectedScriptEnabled) {
                 // Stop any TTS/Vibration right now.
                 onPageLostFocus();
             }
         }
     }

     /**
      * Notifies this handler that a page load has started, which means we should mark the
      * accessibility script as not being injected.  This way we can properly ignore incoming
      * accessibility gesture events.
      */
     @Override
     public void didStartLoading(String url) {
         mScriptInjected = false;
     }

     @Override
     public void didStopLoading(String url) {
         injectAccessibilityScriptIntoPage();
     }

     /**
      * Stop any notifications that are currently going on (e.g. Text-to-Speech).
      */
     public void onPageLostFocus() {
         if (mContentViewCore.isAlive()) {
             if (mTextToSpeech != null) mTextToSpeech.stop();
             if (mVibrator != null) mVibrator.cancel();
         }
     }

     /**
      * Initializes an {@link AccessibilityNodeInfo} with the actions and movement granularity
      * levels supported by this {@link AccessibilityInjector}.
      * <p>
      * If an action identifier is added in this method, this {@link AccessibilityInjector} should
      * also return {@code true} from {@link #supportsAccessibilityAction(int)}.
      * </p>
      *
      * @param info The info to initialize.
      * @see View#onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo)
      */
     public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { }

     /**
      * Returns {@code true} if this {@link AccessibilityInjector} should handle the specified
      * action.
      *
      * @param action An accessibility action identifier.
      * @return {@code true} if this {@link AccessibilityInjector} should handle the specified
      *         action.
      */
     public boolean supportsAccessibilityAction(int action) {
         return false;
     }

     /**
      * Performs the specified accessibility action.
      *
      * @param action The identifier of the action to perform.
      * @param arguments The action arguments, or {@code null} if no arguments.
      * @return {@code true} if the action was successful.
      * @see View#performAccessibilityAction(int, Bundle)
      */
     public boolean performAccessibilityAction(int action, Bundle arguments) {
         return false;
     }

     protected void addAccessibilityApis() {
         Context context = mContentViewCore.getContext();
         if (context != null) {
             // Enabled, we should try to add if we have to.
             if (mTextToSpeech == null) {
                 mTextToSpeech = new TextToSpeechWrapper(mContentViewCore.getContainerView(),
                         context);
                 mContentViewCore.addJavascriptInterface(mTextToSpeech,
                         ALIAS_ACCESSIBILITY_JS_INTERFACE);
             }

             if (mVibrator == null && mHasVibratePermission) {
                 mVibrator = new VibratorWrapper(context);
                 mContentViewCore.addJavascriptInterface(mVibrator,
                         ALIAS_ACCESSIBILITY_JS_INTERFACE_2);
             }
         }
     }

     protected void removeAccessibilityApis() {
         if (mTextToSpeech != null) {
             mContentViewCore.removeJavascriptInterface(ALIAS_ACCESSIBILITY_JS_INTERFACE);
             mTextToSpeech.stop();
             mTextToSpeech.shutdownInternal();
             mTextToSpeech = null;
         }

         if (mVibrator != null) {
             mContentViewCore.removeJavascriptInterface(ALIAS_ACCESSIBILITY_JS_INTERFACE_2);
             mVibrator.cancel();
             mVibrator = null;
         }
     }

     private int getAxsUrlParameterValue() {
         if (mContentViewCore.getWebContents().getUrl() == null) {
             return ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED;
         }

         try {
             List<NameValuePair> params = URLEncodedUtils.parse(
                     new URI(mContentViewCore.getWebContents().getUrl()), null);

             for (NameValuePair param : params) {
                 if ("axs".equals(param.getName())) {
                     return Integer.parseInt(param.getValue());
                 }
             }
         } catch (URISyntaxException ex) {
             // Intentional no-op.
         } catch (NumberFormatException ex) {
             // Intentional no-op.
         } catch (IllegalArgumentException ex) {
             // Intentional no-op.
         }

         return ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED;
     }

     private String getScreenReaderInjectingJs() {
         return String.format(ACCESSIBILITY_SCREEN_READER_JAVASCRIPT_TEMPLATE,
                 mAccessibilityScreenReaderUrl);
     }

     private AccessibilityManager getAccessibilityManager() {
         if (mAccessibilityManager == null) {
             mAccessibilityManager = (AccessibilityManager) mContentViewCore.getContext()
                     .getSystemService(Context.ACCESSIBILITY_SERVICE);
         }

         return mAccessibilityManager;
     }

     /**
      * Used to protect how long JavaScript can vibrate for.  This isn't a good comprehensive
      * protection, just used to cover mistakes and protect against long vibrate durations/repeats.
      *
      * Also only exposes methods we *want* to expose, no others for the class.
      */
     private static class VibratorWrapper {
         private static final long MAX_VIBRATE_DURATION_MS = 5000;

         private final Vibrator mVibrator;

         public VibratorWrapper(Context context) {
             mVibrator = (Vibrator) context.getSystemService(Context.VIBRATOR_SERVICE);
         }

         @JavascriptInterface
         @SuppressWarnings("unused")
         public boolean hasVibrator() {
             return mVibrator.hasVibrator();
         }

         @JavascriptInterface
         @SuppressWarnings("unused")
         public void vibrate(long milliseconds) {
             milliseconds = Math.min(milliseconds, MAX_VIBRATE_DURATION_MS);
             mVibrator.vibrate(milliseconds);
         }

         @JavascriptInterface
         @SuppressWarnings("unused")
         public void vibrate(long[] pattern, int repeat) {
             for (int i = 0; i < pattern.length; ++i) {
                 pattern[i] = Math.min(pattern[i], MAX_VIBRATE_DURATION_MS);
             }

             repeat = -1;

             mVibrator.vibrate(pattern, repeat);
         }

         @JavascriptInterface
         @SuppressWarnings("unused")
         public void cancel() {
             mVibrator.cancel();
         }
     }

     /**
      * Used to protect the TextToSpeech class, only exposing the methods we want to expose.
      */
     private static class TextToSpeechWrapper {
         private final TextToSpeech mTextToSpeech;
         private final SelfBrailleClient mSelfBrailleClient;
         private final View mView;

         public TextToSpeechWrapper(View view, Context context) {
             mView = view;
             mTextToSpeech = new TextToSpeech(context, null, null);
             mSelfBrailleClient = new SelfBrailleClient(context, CommandLine.getInstance().hasSwitch(
                     ContentSwitches.ACCESSIBILITY_DEBUG_BRAILLE_SERVICE));
         }

         @JavascriptInterface
         @SuppressWarnings("unused")
         public boolean isSpeaking() {
             return mTextToSpeech.isSpeaking();
         }

         @JavascriptInterface
         @SuppressWarnings("unused")
         public int speak(String text, int queueMode, String jsonParams) {
             // Try to pull the params from the JSON string.
             HashMap<String, String> params = null;
             try {
                 if (jsonParams != null) {
                     params = new HashMap<String, String>();
                     JSONObject json = new JSONObject(jsonParams);

                     // Using legacy API here.
                     @SuppressWarnings("unchecked")
                     Iterator<String> keyIt = json.keys();

                     while (keyIt.hasNext()) {
                         String key = keyIt.next();
                         // Only add parameters that are raw data types.
                         if (json.optJSONObject(key) == null && json.optJSONArray(key) == null) {
                             params.put(key, json.getString(key));
                         }
                     }
                 }
             } catch (JSONException e) {
                 params = null;
             }

             return mTextToSpeech.speak(text, queueMode, params);
         }

         @JavascriptInterface
         @SuppressWarnings("unused")
         public int stop() {
             return mTextToSpeech.stop();
         }

         @JavascriptInterface
         @SuppressWarnings("unused")
         public void braille(String jsonString) {
             try {
                 JSONObject jsonObj = new JSONObject(jsonString);

                 WriteData data = WriteData.forView(mView);
                 data.setText(jsonObj.getString("text"));
                 data.setSelectionStart(jsonObj.getInt("startIndex"));
                 data.setSelectionEnd(jsonObj.getInt("endIndex"));
                 mSelfBrailleClient.write(data);
             } catch (JSONException ex) {
                 Log.w(TAG, "Error parsing JS JSON object", ex);
             }
         }

         @SuppressWarnings("unused")
         protected void shutdownInternal() {
             mTextToSpeech.shutdown();
             mSelfBrailleClient.shutdown();
         }
     }
 }
	// Copyright 2012 The Chromium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	package org.chromium.content.browser.accessibility;

	import android.accessibilityservice.AccessibilityServiceInfo;
	import android.content.Context;
	import android.content.pm.PackageManager;
	import android.os.Build;
	import android.os.Bundle;
	import android.os.Vibrator;
	import android.speech.tts.TextToSpeech;
	import android.util.Log;
	import android.view.View;
	import android.view.accessibility.AccessibilityManager;
	import android.view.accessibility.AccessibilityNodeInfo;

	import com.googlecode.eyesfree.braille.selfbraille.SelfBrailleClient;
	import com.googlecode.eyesfree.braille.selfbraille.WriteData;

	import org.apache.http.NameValuePair;
	import org.apache.http.client.utils.URLEncodedUtils;
	import org.chromium.base.CommandLine;
	import org.chromium.content.browser.ContentViewCore;
	import org.chromium.content.browser.JavascriptInterface;
	import org.chromium.content.browser.WebContentsObserver;
	import org.chromium.content.common.ContentSwitches;
	import org.json.JSONException;
	import org.json.JSONObject;

	import java.net.URI;
	import java.net.URISyntaxException;
	import java.util.HashMap;
	import java.util.Iterator;
	import java.util.List;

	/**
	* Responsible for accessibility injection and management of a {@link ContentViewCore}.
	*/
	public class AccessibilityInjector extends WebContentsObserver {
	private static final String TAG = "AccessibilityInjector";

	// The ContentView this injector is responsible for managing.
	protected ContentViewCore mContentViewCore;

	// The Java objects that are exposed to JavaScript
	private TextToSpeechWrapper mTextToSpeech;
	private VibratorWrapper mVibrator;
	private final boolean mHasVibratePermission;

	// Lazily loaded helper objects.
	private AccessibilityManager mAccessibilityManager;

	// Whether or not we should be injecting the script.
	protected boolean mInjectedScriptEnabled;
	protected boolean mScriptInjected;

	private final String mAccessibilityScreenReaderUrl;

	// To support building against the JELLY_BEAN and not JELLY_BEAN_MR1 SDK we need to add this
	// constant here.
	private static final int FEEDBACK_BRAILLE = 0x00000020;

	// constants for determining script injection strategy
	private static final int ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED = -1;
	private static final int ACCESSIBILITY_SCRIPT_INJECTION_OPTED_OUT = 0;
	private static final int ACCESSIBILITY_SCRIPT_INJECTION_PROVIDED = 1;
	private static final String ALIAS_ACCESSIBILITY_JS_INTERFACE = "accessibility";
	private static final String ALIAS_ACCESSIBILITY_JS_INTERFACE_2 = "accessibility2";

	// Template for JavaScript that injects a screen-reader.
	private static final String DEFAULT_ACCESSIBILITY_SCREEN_READER_URL =
	"https://ssl.gstatic.com/accessibility/javascript/android/chromeandroidvox.js";

	private static final String ACCESSIBILITY_SCREEN_READER_JAVASCRIPT_TEMPLATE =
	"(function() {"
	+ " var chooser = document.createElement('script');"
	+ " chooser.type = 'text/javascript';"
	+ " chooser.src = '%1s';"
	+ " document.getElementsByTagName('head')[0].appendChild(chooser);"
	+ " })();";

	// JavaScript call to turn ChromeVox on or off.
	private static final String TOGGLE_CHROME_VOX_JAVASCRIPT =
	"(function() {"
	+ " if (typeof cvox !== 'undefined') {"
	+ " cvox.ChromeVox.host.activateOrDeactivateChromeVox(%1s);"
	+ " }"
	+ " })();";

	/**
	* Returns an instance of the {@link AccessibilityInjector} based on the SDK version.
	* @param view The ContentViewCore that this AccessibilityInjector manages.
	* @return An instance of a {@link AccessibilityInjector}.
	*/
	public static AccessibilityInjector newInstance(ContentViewCore view) {
	if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
	return new AccessibilityInjector(view);
	} else {
	return new JellyBeanAccessibilityInjector(view);
	}
	}

	/**
	* Creates an instance of the IceCreamSandwichAccessibilityInjector.
	* @param view The ContentViewCore that this AccessibilityInjector manages.
	*/
	protected AccessibilityInjector(ContentViewCore view) {
	super(view.getWebContents());
	mContentViewCore = view;

	mAccessibilityScreenReaderUrl = CommandLine.getInstance().getSwitchValue(
	ContentSwitches.ACCESSIBILITY_JAVASCRIPT_URL,
	DEFAULT_ACCESSIBILITY_SCREEN_READER_URL);

	mHasVibratePermission = mContentViewCore.getContext().checkCallingOrSelfPermission(
	android.Manifest.permission.VIBRATE) == PackageManager.PERMISSION_GRANTED;
	}

	/**
	* Injects a <script> tag into the current web site that pulls in the ChromeVox script for
	* accessibility support. Only injects if accessibility is turned on by
	* {@link AccessibilityManager#isEnabled()}, accessibility script injection is turned on, and
	* javascript is enabled on this page.
	*
	* @see AccessibilityManager#isEnabled()
	*/
	public void injectAccessibilityScriptIntoPage() {
	if (!accessibilityIsAvailable()) return;

	int axsParameterValue = getAxsUrlParameterValue();
	if (axsParameterValue != ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED) {
	return;
	}

	String js = getScreenReaderInjectingJs();
	if (mContentViewCore.isDeviceAccessibilityScriptInjectionEnabled()
	&& js != null && mContentViewCore.isAlive()) {
	addOrRemoveAccessibilityApisIfNecessary();
	mContentViewCore.getWebContents().evaluateJavaScript(js, null);
	mInjectedScriptEnabled = true;
	mScriptInjected = true;
	}
	}

	/**
	* Handles adding or removing accessibility related Java objects ({@link TextToSpeech} and
	* {@link Vibrator}) interfaces from Javascript. This method should be called at a time when it
	* is safe to add or remove these interfaces, specifically when the {@link ContentViewCore} is
	* first initialized or right before the {@link ContentViewCore} is about to navigate to a URL
	* or reload.
	* <p>
	* If this method is called at other times, the interfaces might not be correctly removed,
	* meaning that Javascript can still access these Java objects that may have been already
	* shut down.
	*/
	public void addOrRemoveAccessibilityApisIfNecessary() {
	if (accessibilityIsAvailable()) {
	addAccessibilityApis();
	} else {
	removeAccessibilityApis();
	}
	}

	/**
	* Checks whether or not touch to explore is enabled on the system.
	*/
	public boolean accessibilityIsAvailable() {
	if (!getAccessibilityManager().isEnabled()
	\|\| mContentViewCore.getContentSettings() == null
	\|\| !mContentViewCore.getContentSettings().getJavaScriptEnabled()) {
	return false;
	}

	try {
	// Check that there is actually a service running that requires injecting this script.
	List<AccessibilityServiceInfo> services =
	getAccessibilityManager().getEnabledAccessibilityServiceList(
	FEEDBACK_BRAILLE \| AccessibilityServiceInfo.FEEDBACK_SPOKEN);
	return services.size() > 0;
	} catch (NullPointerException e) {
	// getEnabledAccessibilityServiceList() can throw an NPE due to a bad
	// AccessibilityService.
	return false;
	}
	}

	/**
	* Sets whether or not the script is enabled. If the script is disabled, we also stop any
	* we output that is occurring. If the script has not yet been injected, injects it.
	* @param enabled Whether or not to enable the script.
	*/
	public void setScriptEnabled(boolean enabled) {
	if (enabled && !mScriptInjected) injectAccessibilityScriptIntoPage();
	if (!accessibilityIsAvailable() \|\| mInjectedScriptEnabled == enabled) return;

	mInjectedScriptEnabled = enabled;
	if (mContentViewCore.isAlive()) {
	String js = String.format(TOGGLE_CHROME_VOX_JAVASCRIPT, Boolean.toString(
	mInjectedScriptEnabled));
	mContentViewCore.getWebContents().evaluateJavaScript(js, null);

	if (!mInjectedScriptEnabled) {
	// Stop any TTS/Vibration right now.
	onPageLostFocus();
	}
	}
	}

	/**
	* Notifies this handler that a page load has started, which means we should mark the
	* accessibility script as not being injected. This way we can properly ignore incoming
	* accessibility gesture events.
	*/
	@Override
	public void didStartLoading(String url) {
	mScriptInjected = false;
	}

	@Override
	public void didStopLoading(String url) {
	injectAccessibilityScriptIntoPage();
	}

	/**
	* Stop any notifications that are currently going on (e.g. Text-to-Speech).
	*/
	public void onPageLostFocus() {
	if (mContentViewCore.isAlive()) {
	if (mTextToSpeech != null) mTextToSpeech.stop();
	if (mVibrator != null) mVibrator.cancel();
	}
	}

	/**
	* Initializes an {@link AccessibilityNodeInfo} with the actions and movement granularity
	* levels supported by this {@link AccessibilityInjector}.
	* <p>
	* If an action identifier is added in this method, this {@link AccessibilityInjector} should
	* also return {@code true} from {@link #supportsAccessibilityAction(int)}.
	* </p>
	*
	* @param info The info to initialize.
	* @see View#onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo)
	*/
	public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { }

	/**
	* Returns {@code true} if this {@link AccessibilityInjector} should handle the specified
	* action.
	*
	* @param action An accessibility action identifier.
	* @return {@code true} if this {@link AccessibilityInjector} should handle the specified
	* action.
	*/
	public boolean supportsAccessibilityAction(int action) {
	return false;
	}

	/**
	* Performs the specified accessibility action.
	*
	* @param action The identifier of the action to perform.
	* @param arguments The action arguments, or {@code null} if no arguments.
	* @return {@code true} if the action was successful.
	* @see View#performAccessibilityAction(int, Bundle)
	*/
	public boolean performAccessibilityAction(int action, Bundle arguments) {
	return false;
	}

	protected void addAccessibilityApis() {
	Context context = mContentViewCore.getContext();
	if (context != null) {
	// Enabled, we should try to add if we have to.
	if (mTextToSpeech == null) {
	mTextToSpeech = new TextToSpeechWrapper(mContentViewCore.getContainerView(),
	context);
	mContentViewCore.addJavascriptInterface(mTextToSpeech,
	ALIAS_ACCESSIBILITY_JS_INTERFACE);
	}

	if (mVibrator == null && mHasVibratePermission) {
	mVibrator = new VibratorWrapper(context);
	mContentViewCore.addJavascriptInterface(mVibrator,
	ALIAS_ACCESSIBILITY_JS_INTERFACE_2);
	}
	}
	}

	protected void removeAccessibilityApis() {
	if (mTextToSpeech != null) {
	mContentViewCore.removeJavascriptInterface(ALIAS_ACCESSIBILITY_JS_INTERFACE);
	mTextToSpeech.stop();
	mTextToSpeech.shutdownInternal();
	mTextToSpeech = null;
	}

	if (mVibrator != null) {
	mContentViewCore.removeJavascriptInterface(ALIAS_ACCESSIBILITY_JS_INTERFACE_2);
	mVibrator.cancel();
	mVibrator = null;
	}
	}

	private int getAxsUrlParameterValue() {
	if (mContentViewCore.getWebContents().getUrl() == null) {
	return ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED;
	}

	try {
	List<NameValuePair> params = URLEncodedUtils.parse(
	new URI(mContentViewCore.getWebContents().getUrl()), null);

	for (NameValuePair param : params) {
	if ("axs".equals(param.getName())) {
	return Integer.parseInt(param.getValue());
	}
	}
	} catch (URISyntaxException ex) {
	// Intentional no-op.
	} catch (NumberFormatException ex) {
	// Intentional no-op.
	} catch (IllegalArgumentException ex) {
	// Intentional no-op.
	}

	return ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED;
	}

	private String getScreenReaderInjectingJs() {
	return String.format(ACCESSIBILITY_SCREEN_READER_JAVASCRIPT_TEMPLATE,
	mAccessibilityScreenReaderUrl);
	}

	private AccessibilityManager getAccessibilityManager() {
	if (mAccessibilityManager == null) {
	mAccessibilityManager = (AccessibilityManager) mContentViewCore.getContext()
	.getSystemService(Context.ACCESSIBILITY_SERVICE);
	}

	return mAccessibilityManager;
	}

	/**
	* Used to protect how long JavaScript can vibrate for. This isn't a good comprehensive
	* protection, just used to cover mistakes and protect against long vibrate durations/repeats.
	*
	* Also only exposes methods we want to expose, no others for the class.
	*/
	private static class VibratorWrapper {
	private static final long MAX_VIBRATE_DURATION_MS = 5000;

	private final Vibrator mVibrator;

	public VibratorWrapper(Context context) {
	mVibrator = (Vibrator) context.getSystemService(Context.VIBRATOR_SERVICE);
	}

	@JavascriptInterface
	@SuppressWarnings("unused")
	public boolean hasVibrator() {
	return mVibrator.hasVibrator();
	}

	@JavascriptInterface
	@SuppressWarnings("unused")
	public void vibrate(long milliseconds) {
	milliseconds = Math.min(milliseconds, MAX_VIBRATE_DURATION_MS);
	mVibrator.vibrate(milliseconds);
	}

	@JavascriptInterface
	@SuppressWarnings("unused")
	public void vibrate(long[] pattern, int repeat) {
	for (int i = 0; i < pattern.length; ++i) {
	pattern[i] = Math.min(pattern[i], MAX_VIBRATE_DURATION_MS);
	}

	repeat = -1;

	mVibrator.vibrate(pattern, repeat);
	}

	@JavascriptInterface
	@SuppressWarnings("unused")
	public void cancel() {
	mVibrator.cancel();
	}
	}

	/**
	* Used to protect the TextToSpeech class, only exposing the methods we want to expose.
	*/
	private static class TextToSpeechWrapper {
	private final TextToSpeech mTextToSpeech;
	private final SelfBrailleClient mSelfBrailleClient;
	private final View mView;

	public TextToSpeechWrapper(View view, Context context) {
	mView = view;
	mTextToSpeech = new TextToSpeech(context, null, null);
	mSelfBrailleClient = new SelfBrailleClient(context, CommandLine.getInstance().hasSwitch(
	ContentSwitches.ACCESSIBILITY_DEBUG_BRAILLE_SERVICE));
	}

	@JavascriptInterface
	@SuppressWarnings("unused")
	public boolean isSpeaking() {
	return mTextToSpeech.isSpeaking();
	}

	@JavascriptInterface
	@SuppressWarnings("unused")
	public int speak(String text, int queueMode, String jsonParams) {
	// Try to pull the params from the JSON string.
	HashMap<String, String> params = null;
	try {
	if (jsonParams != null) {
	params = new HashMap<String, String>();
	JSONObject json = new JSONObject(jsonParams);

	// Using legacy API here.
	@SuppressWarnings("unchecked")
	Iterator<String> keyIt = json.keys();

	while (keyIt.hasNext()) {
	String key = keyIt.next();
	// Only add parameters that are raw data types.
	if (json.optJSONObject(key) == null && json.optJSONArray(key) == null) {
	params.put(key, json.getString(key));
	}
	}
	}
	} catch (JSONException e) {
	params = null;
	}

	return mTextToSpeech.speak(text, queueMode, params);
	}

	@JavascriptInterface
	@SuppressWarnings("unused")
	public int stop() {
	return mTextToSpeech.stop();
	}

	@JavascriptInterface
	@SuppressWarnings("unused")
	public void braille(String jsonString) {
	try {
	JSONObject jsonObj = new JSONObject(jsonString);

	WriteData data = WriteData.forView(mView);
	data.setText(jsonObj.getString("text"));
	data.setSelectionStart(jsonObj.getInt("startIndex"));
	data.setSelectionEnd(jsonObj.getInt("endIndex"));
	mSelfBrailleClient.write(data);
	} catch (JSONException ex) {
	Log.w(TAG, "Error parsing JS JSON object", ex);
	}
	}

	@SuppressWarnings("unused")
	protected void shutdownInternal() {
	mTextToSpeech.shutdown();
	mSelfBrailleClient.shutdown();
	}
	}
	}