Re-land: cc: Add raster finished signals to RasterWorkerPool.

cc/trees/layer_tree_host_unittest_scroll.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 "base/memory/weak_ptr.h"
 #include "cc/layers/content_layer.h"
 #include "cc/layers/layer.h"
 #include "cc/layers/layer_impl.h"
@@ skipping 552 matching lines @@
       // change of main_thread_scroll.
       root->SetScrollOffset(initial_scroll_ + main_thread_scroll_ +
                             impl_thread_scroll1_);
     }
   }
 
   virtual bool CanActivatePendingTree(LayerTreeHostImpl* impl) OVERRIDE {
     return can_activate_;
   }
 
+  virtual bool CanActivatePendingTreeIfNeeded(LayerTreeHostImpl* impl)
+      OVERRIDE {
+    return can_activate_;
+  }
+
   virtual void CommitCompleteOnThread(LayerTreeHostImpl* impl) OVERRIDE {
     // We force a second draw here of the first commit before activating
     // the second commit.
     if (impl->active_tree()->source_frame_number() == 0)
       impl->SetNeedsRedraw();
   }
 
   virtual void DrawLayersOnThread(LayerTreeHostImpl* impl) OVERRIDE {
     ImplSidePaintingScrollTest::DrawLayersOnThread(impl);
 
@@ skipping 255 matching lines @@
     RunTest(true, false, false);
 }
 
 TEST_F(LayerTreeHostScrollTestLayerStructureChange, ScrollDestroyWholeTree) {
     scroll_destroy_whole_tree_ = true;
     RunTest(true, false, false);
 }
 
 }  // namespace
 }  // namespace cc