cc:: Don't use cached screen space transform for layers not in RSLL.

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 <algorithm>
 #include <cmath>
 
 #include "base/bind.h"
@@ skipping 82 matching lines @@
         reduce_memory_result_(true) {
     media::InitializeMediaLibrary();
   }
 
   LayerTreeSettings DefaultSettings() {
     LayerTreeSettings settings;
     settings.minimum_occlusion_tracking_size = gfx::Size();
     settings.renderer_settings.texture_id_allocation_chunk_size = 1;
     settings.gpu_rasterization_enabled = true;
     settings.verify_property_trees = true;
+    settings.use_property_trees = true;

[ajuma, 2015/11/19 01:52:04]

I'd prefer removing this and leaving the settings as-is, so that these tests
switch over to property trees at the same time as other tests.

     return settings;
   }
 
   void SetUp() override {
     CreateHostImpl(DefaultSettings(), CreateOutputSurface());
   }
 
   void TearDown() override {}
 
   void UpdateRendererCapabilitiesOnImplThread() override {}
@@ skipping 4621 matching lines @@
 
     // The root scroll layer should not have scrolled, because the input delta
     // was close to the layer's axis of movement.
     EXPECT_EQ(scroll_info->scrolls.size(), 1u);
   }
 }
 
 TEST_F(LayerTreeHostImplTest, ScrollScaledLayer) {
   LayerImpl* scroll_layer =
       SetupScrollAndContentsLayers(gfx::Size(100, 100));
-  scroll_layer->SetDrawsContent(true);

[jaydasika, 2015/11/19 01:10:11]

We already have a lot of unit test coverage for the changes in this patch. Any
test calling 'ScrollBy' hits the changes by this patch. But, the bug is not
exposed because use_property_trees = false and scroll layer draws content in
most of those tests. So, to test the changes in this patch, I have made use
property trees = true and made scroll layer not draw content in one of the
tests. This modified test fails without the patch.

 
   // Scale the layer to twice its normal size.
   int scale = 2;
   gfx::Transform scale_transform;
   scale_transform.Scale(scale, scale);
   scroll_layer->parent()->SetTransform(scale_transform);
 
   gfx::Size surface_size(50, 50);
   host_impl_->SetViewportSize(surface_size);
   DrawFrame();
@@ skipping 4324 matching lines @@
   host_impl_->active_tree()->SetPageScaleOnActiveTree(2.f);
   DrawFrame();
   in_subtree_of_page_scale_layer = host_impl_->active_tree()->LayerById(100);
   node = host_impl_->active_tree()->property_trees()->transform_tree.Node(
       in_subtree_of_page_scale_layer->transform_tree_index());
   EXPECT_EQ(node->data.sublayer_scale, gfx::Vector2dF(2.f, 2.f));
 }
 
 }  // namespace
 }  // namespace cc