cc: Make scheduling be driven by vsync for android webview.

cc/test/layer_tree_test.cc

Index: cc/test/layer_tree_test.cc
diff --git a/cc/test/layer_tree_test.cc b/cc/test/layer_tree_test.cc
index d6411ecdef251d0dfbcef17cf7cd529bc1ff7d0c..0d65961b85f3cd4c5fbd84c1c8a74dbedf44ca81 100644
--- a/cc/test/layer_tree_test.cc
+++ b/cc/test/layer_tree_test.cc
@@ -61,7 +61,11 @@ class ExternalBeginFrameSourceForTest
   explicit ExternalBeginFrameSourceForTest(double refresh_rate)
       : milliseconds_per_frame_(1000.0 / refresh_rate),
         is_ready_(false),
+        needs_begin_frames_(false),
         weak_ptr_factory_(this) {
+    test_on_begin_frame_closure_ = base::Bind(
+        &ExternalBeginFrameSourceForTest::TestOnBeginFrame,
+        weak_ptr_factory_.GetWeakPtr());
     DetachFromThread();
   }
 
@@ -71,13 +75,10 @@ class ExternalBeginFrameSourceForTest
 
   void OnNeedsBeginFramesChange(bool needs_begin_frames) override {
     DCHECK(CalledOnValidThread());
-    if (needs_begin_frames) {
-      base::MessageLoop::current()->PostDelayedTask(
-        FROM_HERE,
-        base::Bind(&ExternalBeginFrameSourceForTest::TestOnBeginFrame,
-                   weak_ptr_factory_.GetWeakPtr()),
-        base::TimeDelta::FromMilliseconds(milliseconds_per_frame_));
-    }
+    if (needs_begin_frames_ == needs_begin_frames)
+      return;
+    needs_begin_frames_ = needs_begin_frames;
+    ScheduleBeginFrameIfNeeded();
   }
 
   void SetClientReady() override {
@@ -92,11 +93,24 @@ class ExternalBeginFrameSourceForTest
   void TestOnBeginFrame() {
     DCHECK(CalledOnValidThread());
     CallOnBeginFrame(CreateBeginFrameArgsForTesting(BEGINFRAME_FROM_HERE));
+    ScheduleBeginFrameIfNeeded();
+  }
+
+  void ScheduleBeginFrameIfNeeded() {
+    test_on_begin_frame_task_.Cancel();
+    test_on_begin_frame_task_.Reset(test_on_begin_frame_closure_);
+    if (needs_begin_frames_)
+      base::MessageLoop::current()->PostDelayedTask(FROM_HERE,
+          test_on_begin_frame_task_.callback(), 
+          base::TimeDelta::FromMilliseconds(milliseconds_per_frame_));
   }
 
  private:
   double milliseconds_per_frame_;
   bool is_ready_;
+  bool needs_begin_frames_;
+  base::Closure test_on_begin_frame_closure_;
+  base::CancelableClosure test_on_begin_frame_task_;
   base::WeakPtrFactory<ExternalBeginFrameSourceForTest> weak_ptr_factory_;
 };
 
@@ -158,6 +172,11 @@ class ThreadProxyForTest : public ThreadProxy {
     test_hooks_->ScheduledActionPrepareTiles();
   }
 
+  void ScheduledActionInvalidateOutputSurface() override {
+    ThreadProxy::ScheduledActionInvalidateOutputSurface();
+    test_hooks_->ScheduledActionInvalidateOutputSurface();
+  }
+
   ThreadProxyForTest(
       TestHooks* test_hooks,
       LayerTreeHost* host,