cc: Make PrepareToDraw return an enum for why it aborts

cc/trees/layer_tree_host_unittest_animation.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/trees/layer_tree_host.h"
 
 #include "cc/animation/animation_curve.h"
 #include "cc/animation/layer_animation_controller.h"
 #include "cc/animation/scroll_offset_animation_curve.h"
 #include "cc/animation/timing_function.h"
@@ skipping 183 matching lines @@
       LayerTreeHostImpl* host_impl,
       base::TimeTicks monotonic_time) OVERRIDE {
     started_animating_ = true;
   }
 
   virtual void DrawLayersOnThread(LayerTreeHostImpl* host_impl) OVERRIDE {
     if (started_animating_)
       EndTest();
   }
 
-  virtual bool PrepareToDrawOnThread(
+  virtual DrawSwapReadbackResult::DrawResult PrepareToDrawOnThread(
       LayerTreeHostImpl* host_impl,
       LayerTreeHostImpl::FrameData* frame,
-      bool result) OVERRIDE {
-    return false;
+      DrawSwapReadbackResult::DrawResult draw_result) OVERRIDE {
+    return DrawSwapReadbackResult::DRAW_ABORTED_CHECKERBOARD_ANIMATIONS;
   }
 
   virtual void AfterTest() OVERRIDE { }
 
  private:
   bool started_animating_;
 };
 
 // Starvation can only be an issue with the MT compositor.
 MULTI_THREAD_TEST_F(LayerTreeHostAnimationTestCheckerboardDoesNotStarveDraws);
@@ skipping 667 matching lines @@
 
   virtual void BeginTest() OVERRIDE {
     prevented_draw_ = 0;
     added_animations_ = 0;
     started_times_ = 0;
     finished_times_ = 0;
 
     PostSetNeedsCommitToMainThread();
   }
 
-  virtual bool PrepareToDrawOnThread(LayerTreeHostImpl* host_impl,
-                                     LayerTreeHostImpl::FrameData* frame_data,
-                                     bool result) OVERRIDE {
+  virtual DrawSwapReadbackResult::DrawResult PrepareToDrawOnThread(
+      LayerTreeHostImpl* host_impl,
+      LayerTreeHostImpl::FrameData* frame_data,
+      DrawSwapReadbackResult::DrawResult draw_result) OVERRIDE {
     if (added_animations_ < 2)
-      return result;
+      return draw_result;
     if (TestEnded())
-      return result;
+      return draw_result;
     // Act like there is checkerboard when the second animation wants to draw.
     ++prevented_draw_;
-    return false;
+    return DrawSwapReadbackResult::DRAW_ABORTED_CHECKERBOARD_ANIMATIONS;
   }
 
   virtual void DidCommitAndDrawFrame() OVERRIDE {
     switch (layer_tree_host()->source_frame_number()) {
       case 1:
         // The animation is longer than 1 BeginFrame interval.
         AddOpacityTransitionToLayer(content_.get(), 0.1, 0.2f, 0.8f, false);
         added_animations_++;
         break;
       case 2:
@@ skipping 92 matching lines @@
   FakeContentLayerClient client_;
   scoped_refptr<FakeContentLayer> scroll_layer_;
 };
 
 // SingleThreadProxy doesn't send scroll updates from LayerTreeHostImpl to
 // LayerTreeHost.
 MULTI_THREAD_TEST_F(LayerTreeHostAnimationTestScrollOffsetChangesArePropagated);
 
 }  // namespace
 }  // namespace cc