Remove ColorFade resouces when screen off.

This will not destroy the surface but will free up everything else used by
ColorFade when the screen is turned off. When it is turned on the surface is
dismissed.

Bug: 24371570

Change-Id: Iba455cdf225a68b320896f8b35d1e873e694b1e3
diff --git a/services/core/java/com/android/server/display/ColorFade.java b/services/core/java/com/android/server/display/ColorFade.java
index bb4dbc3..835ba17 100644
--- a/services/core/java/com/android/server/display/ColorFade.java
+++ b/services/core/java/com/android/server/display/ColorFade.java
@@ -74,6 +74,7 @@
 
     // Set to true when the animation context has been fully prepared.
     private boolean mPrepared;
+    private boolean mCreatedResources;
     private int mMode;
 
     private final DisplayManagerInternal mDisplayManagerInternal;
@@ -169,6 +170,7 @@
         }
 
         // Done.
+        mCreatedResources = true;
         mPrepared = true;
 
         // Dejanking optimization.
@@ -313,6 +315,34 @@
     }
 
     /**
+     * Dismisses the color fade animation resources.
+     *
+     * This function destroys the resources that are created for the color fade
+     * animation but does not clean up the surface.
+     */
+    public void dismissResources() {
+        if (DEBUG) {
+            Slog.d(TAG, "dismissResources");
+        }
+
+        if (mCreatedResources) {
+            attachEglContext();
+            try {
+                destroyScreenshotTexture();
+                destroyGLShaders();
+                destroyGLBuffers();
+                destroyEglSurface();
+            } finally {
+                detachEglContext();
+            }
+            // This is being called with no active context so shouldn't be
+            // needed but is safer to not change for now.
+            GLES20.glFlush();
+            mCreatedResources = false;
+        }
+    }
+
+    /**
      * Dismisses the color fade animation surface and cleans up.
      *
      * To prevent stray photons from leaking out after the color fade has been
@@ -325,17 +355,8 @@
         }
 
         if (mPrepared) {
-            attachEglContext();
-            try {
-                destroyScreenshotTexture();
-                destroyGLShaders();
-                destroyGLBuffers();
-                destroyEglSurface();
-            } finally {
-                detachEglContext();
-            }
+            dismissResources();
             destroySurface();
-            GLES20.glFlush();
             mPrepared = false;
         }
     }
diff --git a/services/core/java/com/android/server/display/DisplayPowerController.java b/services/core/java/com/android/server/display/DisplayPowerController.java
index 452378f..7b49530 100644
--- a/services/core/java/com/android/server/display/DisplayPowerController.java
+++ b/services/core/java/com/android/server/display/DisplayPowerController.java
@@ -837,6 +837,7 @@
         if (mPendingScreenOff && target != Display.STATE_OFF) {
             setScreenState(Display.STATE_OFF);
             mPendingScreenOff = false;
+            mPowerState.dismissColorFadeResources();
         }
 
         if (target == Display.STATE_ON) {
@@ -910,6 +911,7 @@
                 // A black surface is already hiding the contents of the screen.
                 setScreenState(Display.STATE_OFF);
                 mPendingScreenOff = false;
+                mPowerState.dismissColorFadeResources();
             } else if (performScreenOffTransition
                     && mPowerState.prepareColorFade(mContext,
                             mColorFadeFadesConfig ?
diff --git a/services/core/java/com/android/server/display/DisplayPowerState.java b/services/core/java/com/android/server/display/DisplayPowerState.java
index 2eabd32..9862516 100644
--- a/services/core/java/com/android/server/display/DisplayPowerState.java
+++ b/services/core/java/com/android/server/display/DisplayPowerState.java
@@ -187,7 +187,7 @@
     }
 
     /**
-     * Dismisses the electron beam surface.
+     * Dismisses the color fade surface.
      */
     public void dismissColorFade() {
         mColorFade.dismiss();
@@ -195,6 +195,13 @@
         mColorFadeReady = true;
     }
 
+   /**
+     * Dismisses the color fade resources.
+     */
+    public void dismissColorFadeResources() {
+        mColorFade.dismissResources();
+    }
+
     /**
      * Sets the level of the electron beam steering current.
      *