Add explicit exported tags

Bug: 195988762
Test: make javac-check
Change-Id: Ifd07672da0141c74ad32613a17691c6cd09e54de
diff --git a/samples/MultiDisplay/AndroidManifest.xml b/samples/MultiDisplay/AndroidManifest.xml
index 81aa43b..18f9f88 100644
--- a/samples/MultiDisplay/AndroidManifest.xml
+++ b/samples/MultiDisplay/AndroidManifest.xml
@@ -27,7 +27,8 @@
             android:label="@string/md_launcher"
             android:theme="@style/LauncherTheme"
             android:launchMode="singleTop"
-            android:configChanges="orientation|screenSize|smallestScreenSize|screenLayout|colorMode|density">
+            android:configChanges="orientation|screenSize|smallestScreenSize|screenLayout|colorMode|density"
+            android:exported="true">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.HOME" />
@@ -39,7 +40,8 @@
 
         <service
             android:name=".wallpaper.SampleWallpaper"
-            android:permission="android.permission.BIND_WALLPAPER">
+            android:permission="android.permission.BIND_WALLPAPER"
+            android:exported="true">
             <intent-filter>
                 <action android:name="android.service.wallpaper.WallpaperService">
                 </action>
@@ -52,4 +54,4 @@
     </application>
 
 
-</manifest>
\ No newline at end of file
+</manifest>
diff --git a/samples/ShortcutDemo/launcher/AndroidManifest.xml b/samples/ShortcutDemo/launcher/AndroidManifest.xml
index 581079a..b024385 100644
--- a/samples/ShortcutDemo/launcher/AndroidManifest.xml
+++ b/samples/ShortcutDemo/launcher/AndroidManifest.xml
@@ -21,7 +21,8 @@
 
     <application android:label="@string/app_title"
         android:resizeableActivity="true">
-        <activity android:name="ShortcutLauncherMain">
+        <activity android:name="ShortcutLauncherMain"
+            android:exported="true">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.DEFAULT" />
diff --git a/samples/WiFiDirectDemo/AndroidManifest.xml b/samples/WiFiDirectDemo/AndroidManifest.xml
index 759c4cc..eb2a90f 100644
--- a/samples/WiFiDirectDemo/AndroidManifest.xml
+++ b/samples/WiFiDirectDemo/AndroidManifest.xml
@@ -22,6 +22,7 @@
         android:theme="@android:style/Theme.Holo">
         <activity
             android:name=".WiFiDirectActivity"
+            android:exported="true"
             android:label="@string/app_name" android:launchMode="singleTask">
             <intent-filter>
                 <action