cc: Allow the main thread to cancel commits

cc/trees/layer_tree_host_unittest_damage.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/test/fake_content_layer.h"
 #include "cc/test/fake_content_layer_client.h"
 #include "cc/test/layer_tree_test.h"
 #include "cc/trees/damage_tracker.h"
@@ skipping 65 matching lines @@
   virtual void DidCommit() OVERRIDE {
     int next_frame = layer_tree_host()->commit_number();
     switch (next_frame) {
       case 1:
         layer_tree_host()->SetNeedsCommit();
         break;
       case 2:
         // Cause visible damage.
         content_->SetNeedsDisplayRect(
             gfx::Rect(layer_tree_host()->device_viewport_size()));
+        layer_tree_host()->SetNeedsCommit();

[danakj, 2013/07/18 21:57:23]

This is a ContentLayer, so won't damaging the layer in a visible area cause it
to commit?

[enne (OOO), 2013/07/19 01:23:51]

Quite right.  Removed this.

         break;
       case 3:
         // Cause non-visible damage.
         content_->SetNeedsDisplayRect(gfx::Rect(1990, 1990, 10, 10));
+        layer_tree_host()->SetNeedsCommit();
         break;
     }
   }
 
   virtual void AfterTest() OVERRIDE {
     EXPECT_EQ(4, did_swaps_);
     EXPECT_EQ(2, expect_swap_and_succeed_);
     EXPECT_EQ(expect_swap_and_succeed_, did_swap_and_succeed_);
   }
 
@@ skipping 179 matching lines @@
   FakeContentLayerClient client_;
   scoped_refptr<FakeContentLayer> root_;
   scoped_refptr<FakeContentLayer> child_;
   gfx::RectF child_damage_rect_;
 };
 
 SINGLE_AND_MULTI_THREAD_TEST_F(LayerTreeHostDamageTestForcedFullDamage);
 
 }  // namespace
 }  // namespace cc