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

services/core/java/com/android/server/display/ColorFade.java

@@ -74,6 +74,7 @@ final class ColorFade {
 
     // 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 @@ final class ColorFade {
         }
 
         // Done.
+        mCreatedResources = true;
         mPrepared = true;
 
         // Dejanking optimization.
@@ -312,6 +314,34 @@ final class ColorFade {
         vtx.put(7, y);
     }
 
+    /**
+     * 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.
      *
@@ -325,17 +355,8 @@ final class ColorFade {
         }
 
         if (mPrepared) {
-            attachEglContext();
-            try {
-                destroyScreenshotTexture();
-                destroyGLShaders();
-                destroyGLBuffers();
-                destroyEglSurface();
-            } finally {
-                detachEglContext();
-            }
+            dismissResources();
             destroySurface();
-            GLES20.glFlush();
             mPrepared = false;
         }
     }

services/core/java/com/android/server/display/DisplayPowerController.java

@@ -837,6 +837,7 @@ final class DisplayPowerController implements AutomaticBrightnessController.Call
         if (mPendingScreenOff && target != Display.STATE_OFF) {
             setScreenState(Display.STATE_OFF);
             mPendingScreenOff = false;
+            mPowerState.dismissColorFadeResources();
         }
 
         if (target == Display.STATE_ON) {
@@ -910,6 +911,7 @@ final class DisplayPowerController implements AutomaticBrightnessController.Call
                 // 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 ?

services/core/java/com/android/server/display/DisplayPowerState.java

@@ -187,7 +187,7 @@ final class DisplayPowerState {
     }
 
     /**
-     * Dismisses the electron beam surface.
+     * Dismisses the color fade surface.
      */
     public void dismissColorFade() {
         mColorFade.dismiss();
@@ -195,6 +195,13 @@ final class DisplayPowerState {
         mColorFadeReady = true;
     }
 
+   /**
+     * Dismisses the color fade resources.
+     */
+    public void dismissColorFadeResources() {
+        mColorFade.dismissResources();
+    }
+
     /**
      * Sets the level of the electron beam steering current.
      *