cc : Track ids for which active opacity always wins on property trees

cc/trees/layer_tree_host_impl_unittest.cc

 // Copyright 2011 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_impl.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <cmath>
@@ skipping 2869 matching lines @@
     host_impl_->ScrollbarAnimationControllerForId(scroll->id())
         ->DidMouseMoveNear(0);
     host_impl_->ScrollBegin(BeginState(gfx::Point()).get(),
                             InputHandler::WHEEL);
     host_impl_->ScrollBy(UpdateState(gfx::Point(), gfx::Vector2dF(0, 5)).get());
     host_impl_->ScrollEnd(EndState().get());
     host_impl_->CreatePendingTree();
     EffectNode* pending_tree_node =
         host_impl_->pending_tree()->property_trees()->effect_tree.Node(
             scrollbar_layer->effect_tree_index());
+    LayerImpl* pending_scrollbar_layer =
+        host_impl_->pending_tree()->LayerById(400);
+    host_impl_->pending_tree()
+        ->property_trees()
+        ->always_use_active_tree_opacity_effect_ids.push_back(400);
     EXPECT_FLOAT_EQ(1.f, active_tree_node->data.opacity);
     EXPECT_FLOAT_EQ(1.f, scrollbar_layer->opacity());
     EXPECT_FLOAT_EQ(0.f, pending_tree_node->data.opacity);
+    pending_scrollbar_layer->SetNeedsPushProperties();

[ajuma, 2016/05/18 13:53:48]

Is this line needed?

[jaydasika, 2016/05/19 00:27:09]

I added this when I realized ScrollbarlayerImplBase::PushPropertiesTo was not
getting called during the activation here. So, scrollbar_layer->opacity() was
not really getting tested. The active opacity remains because we don't push
properties and not because PushPropertiesTo ensures it. But, given that we are
going to delete LayerImpl::opacity soon, I think its not needed.

     host_impl_->ActivateSyncTree();
     active_tree_node =
         host_impl_->active_tree()->property_trees()->effect_tree.Node(
             scrollbar_layer->effect_tree_index());
     EXPECT_FLOAT_EQ(1.f, active_tree_node->data.opacity);
     EXPECT_FLOAT_EQ(1.f, scrollbar_layer->opacity());
   }
 };
 
 TEST_F(LayerTreeHostImplTestScrollbarOpacity, LinearFade) {
@@ skipping 7844 matching lines @@
 
   // Re-initialize with a software output surface.
   output_surface_ = FakeOutputSurface::CreateSoftware(
       base::WrapUnique(new SoftwareOutputDevice));
   host_impl_->InitializeRenderer(output_surface_.get());
   EXPECT_FALSE(host_impl_->use_gpu_rasterization());
 }
 
 }  // namespace
 }  // namespace cc