cc: Prevent unit tests from using Now() as the impl frame time.

cc/test/fake_layer_tree_host_impl.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_layer_tree_host_impl.h"
 #include "cc/test/test_shared_bitmap_manager.h"
 #include "cc/trees/layer_tree_impl.h"
 
 namespace cc {
 
 FakeLayerTreeHostImpl::FakeLayerTreeHostImpl(Proxy* proxy,
                                              SharedBitmapManager* manager)
     : LayerTreeHostImpl(LayerTreeSettings(),
                         &client_,
                         proxy,
                         &stats_instrumentation_,
                         manager,
                         0) {
   // Explicitly clear all debug settings.
   SetDebugState(LayerTreeDebugState());
   SetViewportSize(gfx::Size(100, 100));
+
+  // Avoid using Now() as the frame time in unit tests.

[enne (OOO), 2014/08/06 23:49:38]

Random thought: is this something we could/should presubmit ban, in another
test?

[danakj, 2014/08/07 03:36:11]

Well. Its not the tests doing Now() explicitly. Its that they didn't set a
current frame time ticks. And LTHI uses Now(). Its horrible and we should make
LTHI stop using Now() really. Not sure how to guard this for other tests tho :/

+  base::TimeTicks time_ticks = base::TimeTicks::FromInternalValue(1);
+  SetCurrentFrameTimeTicks(time_ticks);
 }
 
 FakeLayerTreeHostImpl::FakeLayerTreeHostImpl(const LayerTreeSettings& settings,
                                              Proxy* proxy,
                                              SharedBitmapManager* manager)
     : LayerTreeHostImpl(settings,
                         &client_,
                         proxy,
                         &stats_instrumentation_,
                         manager,
                         0) {
   // Explicitly clear all debug settings.
   SetDebugState(LayerTreeDebugState());
+
+  // Avoid using Now() as the frame time in unit tests.
+  base::TimeTicks time_ticks = base::TimeTicks::FromInternalValue(1);
+  SetCurrentFrameTimeTicks(time_ticks);
 }
 
 FakeLayerTreeHostImpl::~FakeLayerTreeHostImpl() {}
 
 void FakeLayerTreeHostImpl::CreatePendingTree() {
   LayerTreeHostImpl::CreatePendingTree();
   float arbitrary_large_page_scale = 100000.f;
   pending_tree()->SetPageScaleFactorAndLimits(
       1.f, 1.f / arbitrary_large_page_scale, arbitrary_large_page_scale);
 }
 
 base::TimeTicks FakeLayerTreeHostImpl::CurrentFrameTimeTicks() {
   if (current_frame_time_ticks_.is_null())
     return LayerTreeHostImpl::CurrentFrameTimeTicks();
   return current_frame_time_ticks_;
 }
 
 void FakeLayerTreeHostImpl::SetCurrentFrameTimeTicks(
     base::TimeTicks current_frame_time_ticks) {
   current_frame_time_ticks_ = current_frame_time_ticks;
 }
 
 }  // namespace cc