aw: Fix HardwareView for instrumentation tests

* Implement detachGLFunctor. The contract here is after detachGLFunctor
  is called, DrawGL is no longer called until the next requestDrawGL.
  Implement just with a mFunctorAttached variable.
* Only create one HardwareView. Each GLSurfaceView creates its own GL
  thread, but we only assume a single render thread. Using SurfaceView
  or hosting multiple AwContents in the same GLSurfaceView is too hard,
  so just do the simplest thing, and create the first view has hardware
  accelerated.

BUG=416981

Review URL: https://codereview.chromium.org/594333002

Cr-Commit-Position: refs/heads/master@{#296261}

android_webview/test/shell/src/org/chromium/android_webview/test/AwTestContainerView.java

@@ -52,6 +52,7 @@ public class AwTestContainerView extends FrameLayout {
         // and drawGL on the rendering thread. The variables following
         // are protected by it.
         private final Object mSyncLock = new Object();
+        private boolean mFunctorAttached = false;
         private boolean mNeedsProcessGL = false;
         private boolean mNeedsDrawGL = false;
         private boolean mWaitForCompletion = false;
@@ -135,9 +136,19 @@ public class AwTestContainerView extends FrameLayout {
             }
         }
 
+        public void detachGLFunctor() {
+            synchronized (mSyncLock) {
+                mFunctorAttached = false;
+                mNeedsProcessGL = false;
+                mNeedsDrawGL = false;
+                mWaitForCompletion = false;
+            }
+        }
+
         public void requestRender(Canvas canvas, boolean waitForCompletion) {
             synchronized (mSyncLock) {
                 super.requestRender();
+                mFunctorAttached = true;
                 mWaitForCompletion = waitForCompletion;
                 if (canvas == null) {
                     mNeedsProcessGL = true;
@@ -173,6 +184,11 @@ public class AwTestContainerView extends FrameLayout {
             final boolean waitForCompletion;
 
             synchronized (mSyncLock) {
+                if (!mFunctorAttached) {
+                    mSyncLock.notifyAll();
+                    return;
+                }
+
                 draw = mNeedsDrawGL;
                 process = mNeedsProcessGL;
                 waitForCompletion = mWaitForCompletion;
@@ -204,14 +220,25 @@ public class AwTestContainerView extends FrameLayout {
         }
     }
 
+    private static boolean sCreatedOnce = false;
+    private HardwareView createHardwareViewOnlyOnce(Context context) {
+        if (sCreatedOnce) return null;
+        sCreatedOnce = true;
+        return new HardwareView(context);
+    }
+
     public AwTestContainerView(Context context, boolean hardwareAccelerated) {
         super(context);
         if (hardwareAccelerated) {
-            mHardwareView = new HardwareView(context);
+            mHardwareView = createHardwareViewOnlyOnce(context);
+        }
+        if (mHardwareView != null) {
             addView(mHardwareView,
                     new FrameLayout.LayoutParams(
                         FrameLayout.LayoutParams.MATCH_PARENT,
                         FrameLayout.LayoutParams.MATCH_PARENT));
+        } else {
+          setLayerType(LAYER_TYPE_SOFTWARE, null);
         }
         mNativeGLDelegate = new NativeGLDelegate();
         mInternalAccessDelegate = new InternalAccessAdapter();
@@ -396,7 +423,7 @@ public class AwTestContainerView extends FrameLayout {
 
         @Override
         public void detachGLFunctor() {
-            // Intentional no-op.
+            if (mHardwareView != null) mHardwareView.detachGLFunctor();
         }
     }