cc: Use multiple PrepareTiles approaches

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 589 matching lines @@
     LayerTreeHostAnimationTest::SetupTree();
     content_ = FakeContentLayer::Create(&client_);
     content_->SetBounds(gfx::Size(4, 4));
     content_->set_layer_animation_delegate(this);
     layer_tree_host()->root_layer()->AddChild(content_);
   }
 
   void InitializeSettings(LayerTreeSettings* settings) override {
     // Make sure that drawing many times doesn't cause a checkerboarded
     // animation to start so we avoid flake in this test.
-    settings->timeout_and_draw_when_animation_checkerboards = false;
+    // TODO(brianderson): Figure out what to do to make this test not flaky.
+    // settings->timeout_and_draw_when_animation_checkerboards = false;
   }
 
   void BeginTest() override {
     prevented_draw_ = 0;
     added_animations_ = 0;
     started_times_ = 0;
 
     PostSetNeedsCommitToMainThread();
   }
 
@@ skipping 364 matching lines @@
  private:
   scoped_refptr<Layer> content_;
   int num_swap_buffers_;
 };
 
 SINGLE_AND_MULTI_THREAD_TEST_F(
     LayerTreeHostAnimationTestAddAnimationAfterAnimating);
 
 }  // namespace
 }  // namespace cc