android: Add draw completion for CompositorView

chrome/android/java/src/org/chromium/chrome/browser/compositor/CompositorView.java

Index: chrome/android/java/src/org/chromium/chrome/browser/compositor/CompositorView.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/compositor/CompositorView.java b/chrome/android/java/src/org/chromium/chrome/browser/compositor/CompositorView.java
index a6f7e7aba7142e03615502236f168d3d7f8aaec5..8fb536635630804908b240569e364c7eb7b11c28 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/compositor/CompositorView.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/compositor/CompositorView.java
@@ -23,6 +23,7 @@ import org.chromium.base.Log;
 import org.chromium.base.TraceEvent;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
+import org.chromium.base.annotations.UsedByReflection;
 import org.chromium.chrome.browser.ChromeSwitches;
 import org.chromium.chrome.browser.compositor.layouts.Layout;
 import org.chromium.chrome.browser.compositor.layouts.LayoutProvider;
@@ -39,12 +40,14 @@ import org.chromium.ui.base.WindowAndroid;
 import org.chromium.ui.resources.AndroidResourceType;
 import org.chromium.ui.resources.ResourceManager;
 
+import java.util.ArrayList;
+import java.util.List;
+
 /**
  * The is the {@link View} displaying the ui compositor results; including webpages and tabswitcher.
  */
 @JNINamespace("android")
-public class CompositorView
-        extends SurfaceView implements SurfaceHolder.Callback {
+public class CompositorView extends SurfaceView implements SurfaceHolder.Callback2 {
     private static final String TAG = "CompositorView";
     private static final long NANOSECONDS_PER_MILLISECOND = 1000000;
 
@@ -73,6 +76,7 @@ public class CompositorView
     private int mSurfaceWidth;
     private int mSurfaceHeight;
     private boolean mPreloadedResources;
+    private List<Runnable> mDrawingFinishedCallbacks;
 
     // The current SurfaceView pixel format. Defaults to OPAQUE.
     private int mCurrentPixelFormat = PixelFormat.OPAQUE;
@@ -200,6 +204,9 @@ public class CompositorView
 
         // Grab the Resource Manager
         mResourceManager = nativeGetResourceManager(mNativeCompositorView);
+
+        // Redraw in case there are callbacks pending |mDrawingFinishedCallbacks|.
+        nativeSetNeedsComposite(mNativeCompositorView);
     }
 
     @Override
@@ -218,6 +225,19 @@ public class CompositorView
     }
 
     @Override
+    public void surfaceRedrawNeeded(SurfaceHolder holder) {
+        // Intentionally not implemented.
+    }
+
+    // TODO(boliu): Mark this override instead.
+    @UsedByReflection("Android")
+    public void surfaceRedrawNeededAsync(SurfaceHolder holder, Runnable drawingFinished) {
+        if (mDrawingFinishedCallbacks == null) mDrawingFinishedCallbacks = new ArrayList<>();
+        mDrawingFinishedCallbacks.add(drawingFinished);
+        if (mNativeCompositorView != 0) nativeSetNeedsComposite(mNativeCompositorView);
+    }
+
+    @Override
     public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
         if (mNativeCompositorView == 0) return;
         nativeSurfaceChanged(mNativeCompositorView, format, width, height, holder.getSurface());
@@ -311,6 +331,16 @@ public class CompositorView
         mRenderHost.didSwapFrame(pendingFrameCount);
     }
 
+    @CalledByNative
+    private void didSwapBuffers() {
+        List<Runnable> runnables = mDrawingFinishedCallbacks;
+        mDrawingFinishedCallbacks = null;
+        if (runnables == null) return;
+        for (Runnable r : runnables) {

[Ted C, 2017/03/03 21:00:16]

drive by nit but since this is an ArrayList, you should use the for (int i = 0;
i <...) here because this will allocate an iterator (and you don't have an
LinkedList were it would be expensive).

[boliu, 2017/03/03 21:04:05]

Wait, is linked list less expensive?

+            r.run();
+        }
+    }
+
     /**
      * Converts the layout into compositor layers. This is to be called on every frame the layout
      * is changing.