Keeping track of descendants that draw content instead of recalcualting

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 <cmath>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 1844 matching lines @@
       static_cast<DidDrawCheckLayer*>(layer1->children()[0]);
 
   layer1->SetOpacity(0.3f);
   layer1->SetShouldFlattenTransform(true);
 
   EXPECT_FALSE(root->did_draw_called());
   EXPECT_FALSE(layer1->did_draw_called());
   EXPECT_FALSE(layer2->did_draw_called());
 
   LayerTreeHostImpl::FrameData frame;
+  FakeLayerTreeHostImpl::UpdateNumChildrenAndDrawProperties(

[danakj, 2014/08/06 14:57:08]

PrepareToDraw does an UpdateDrawProps, why do we need to do that as well here?

[awoloszyn, 2014/08/08 15:53:21]

We do not need it. Will change.

+      host_impl_->active_tree());
   EXPECT_EQ(DRAW_SUCCESS, host_impl_->PrepareToDraw(&frame));
   host_impl_->DrawLayers(&frame);
   host_impl_->DidDrawAllLayers(frame);
 
   EXPECT_TRUE(root->did_draw_called());
   EXPECT_TRUE(layer1->did_draw_called());
   EXPECT_TRUE(layer2->did_draw_called());
 
   EXPECT_NE(root->render_surface(), layer1->render_surface());
   EXPECT_TRUE(!!layer1->render_surface());
@@ skipping 1813 matching lines @@
   // drawing child, it's drawn to a render surface which carries the opacity,
   // so it's itself drawn without blending.
   // Child layer with opaque content, drawn without blending (parent surface
   // carries the inherited opacity).
   layer1->SetContentsOpaque(true);
   layer1->SetOpacity(0.5f);
   layer1->SetExpectation(false, true);
   layer1->SetUpdateRect(gfx::RectF(layer1->content_bounds()));
   layer2->SetExpectation(false, false);
   layer2->SetUpdateRect(gfx::RectF(layer1->content_bounds()));
+  FakeLayerTreeHostImpl::UpdateNumChildrenAndDrawProperties(

[danakj, 2014/08/06 14:57:08]

Same question

[awoloszyn, 2014/08/08 15:53:21]

Same.

+      host_impl_->active_tree());
   EXPECT_EQ(DRAW_SUCCESS, host_impl_->PrepareToDraw(&frame));
   host_impl_->DrawLayers(&frame);
   EXPECT_TRUE(layer1->quads_appended());
   EXPECT_TRUE(layer2->quads_appended());
   host_impl_->DidDrawAllLayers(frame);
 
   // Draw again, but with child non-opaque, to make sure
   // layer1 not culled.
   layer1->SetContentsOpaque(true);
   layer1->SetOpacity(1.f);
@@ skipping 3054 matching lines @@
 
   host_impl_->Animate(start_time + base::TimeDelta::FromMilliseconds(200));
   host_impl_->UpdateAnimationState(true);
 
   EXPECT_EQ(gfx::Vector2dF(0, 50), scrolling_layer->TotalScrollOffset());
   EXPECT_EQ(NULL, host_impl_->CurrentlyScrollingLayer());
 }
 
 }  // namespace
 }  // namespace cc