Turn off computation of the interest rect in cc in synchronized paint mode.

cc/test/fake_content_layer_client.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/test/fake_content_layer_client.h"
 
 #include "cc/playback/clip_display_item.h"
 #include "cc/playback/display_item_list_settings.h"
 #include "cc/playback/drawing_display_item.h"
 #include "cc/playback/transform_display_item.h"
@@ skipping 17 matching lines @@
 
 FakeContentLayerClient::FakeContentLayerClient()
     : fill_with_nonsolid_color_(false),
       last_canvas_(nullptr),
       last_painting_control_(PAINTING_BEHAVIOR_NORMAL),
       reported_memory_usage_(0) {}
 
 FakeContentLayerClient::~FakeContentLayerClient() {
 }
 
+gfx::Rect FakeContentLayerClient::PaintableRegion() {
+  CHECK(bounds_set_);

[enne (OOO), 2015/11/18 21:31:58]

I get that you're trying to check that you covered everything.  But, not all of
these tests actually paint anything.

What do you think about just setting this to a default value of an empty rect so
that every test that uses a FakeContentLayerClient doesn't have to update this
value?

[chrishtr, 2015/11/18 22:33:11]

Per offline conversation, there were actually a whole bunch of tests that failed
that tried to draw tiles. I don't know the exact percentage, but I think it was
enough to make it reasonable to just leave it.

+  return gfx::Rect(bounds_);
+}
+
 scoped_refptr<DisplayItemList>
 FakeContentLayerClient::PaintContentsToDisplayList(
     const gfx::Rect& clip,
     PaintingControlSetting painting_control) {
   // Cached picture is used because unit tests expect to be able to
   // use GatherPixelRefs.
   DisplayItemListSettings settings;
   settings.use_cached_picture = true;
   scoped_refptr<DisplayItemList> display_list =
       DisplayItemList::Create(clip, settings);
@@ skipping 55 matching lines @@
   return display_list;
 }
 
 bool FakeContentLayerClient::FillsBoundsCompletely() const { return false; }
 
 size_t FakeContentLayerClient::GetApproximateUnsharedMemoryUsage() const {
   return reported_memory_usage_;
 }
 
 }  // namespace cc