Replace LayerImpl::sorting_context_id with transform reference.

cc/layers/solid_color_layer_impl_unittest.cc

Index: cc/layers/solid_color_layer_impl_unittest.cc
diff --git a/cc/layers/solid_color_layer_impl_unittest.cc b/cc/layers/solid_color_layer_impl_unittest.cc
index d2e2bb86dac9c30a47fa5bccd4fec018da37f473..b5c8dd14d390c5ab280a450a0e1f3c4fe356270c 100644
--- a/cc/layers/solid_color_layer_impl_unittest.cc
+++ b/cc/layers/solid_color_layer_impl_unittest.cc
@@ -38,9 +38,11 @@ TEST(SolidColorLayerImplTest, VerifyTilingCompleteAndNoOverlap) {
   layer->draw_properties().visible_layer_rect = visible_layer_rect;
   layer->SetBounds(layer_size);
   layer->test_properties()->force_render_surface = true;
-
+  host_impl.active_tree()->SetRootLayerForTesting(std::move(layer));
+  host_impl.active_tree()->BuildPropertyTreesForTesting();
   AppendQuadsData data;
-  layer->AppendQuads(render_pass.get(), &data);
+  host_impl.active_tree()->root_layer_for_testing()->AppendQuads(
+      render_pass.get(), &data);
 
   LayerTestCommon::VerifyQuadsExactlyCoverRect(render_pass->quad_list,
                                                visible_layer_rect);
@@ -63,9 +65,11 @@ TEST(SolidColorLayerImplTest, VerifyCorrectBackgroundColorInQuad) {
   layer->SetBounds(layer_size);
   layer->SetBackgroundColor(test_color);
   layer->test_properties()->force_render_surface = true;
-
+  host_impl.active_tree()->SetRootLayerForTesting(std::move(layer));
+  host_impl.active_tree()->BuildPropertyTreesForTesting();
   AppendQuadsData data;
-  layer->AppendQuads(render_pass.get(), &data);
+  host_impl.active_tree()->root_layer_for_testing()->AppendQuads(
+      render_pass.get(), &data);
 
   ASSERT_EQ(render_pass->quad_list.size(), 1U);
   EXPECT_EQ(
@@ -90,9 +94,11 @@ TEST(SolidColorLayerImplTest, VerifyCorrectOpacityInQuad) {
   layer->SetBounds(layer_size);
   layer->draw_properties().opacity = opacity;
   layer->test_properties()->force_render_surface = true;
-
+  host_impl.active_tree()->SetRootLayerForTesting(std::move(layer));
+  host_impl.active_tree()->BuildPropertyTreesForTesting();
   AppendQuadsData data;
-  layer->AppendQuads(render_pass.get(), &data);
+  host_impl.active_tree()->root_layer_for_testing()->AppendQuads(
+      render_pass.get(), &data);
 
   ASSERT_EQ(render_pass->quad_list.size(), 1U);
   EXPECT_EQ(opacity,
@@ -100,29 +106,6 @@ TEST(SolidColorLayerImplTest, VerifyCorrectOpacityInQuad) {
                 ->shared_quad_state->opacity);
 }
 
-TEST(SolidColorLayerImplTest, VerifyCorrectBlendModeInQuad) {

[wkorman, 2017/01/06 22:50:02]

I spent a bunch of time looking at this test and roped in ericrk@ to consult. We
believe it is testing a scenario that never happens in the wild, and so is not
relevant and we can just delete the test case.

If we build a property tree for this test case, and set blend mode in the
layer_impl test_properties(), and even if we try creating a root layer and
hanging the solid color layer off of that as a child layer, in all situations we
end up hitting this case in PropertyTreeBuilder:

https://cs.chromium.org/chromium/src/cc/trees/property_tree_builder.cc?q=prop...

which overwrites the layer draw blend mode with kSrcOver. When we have it set up
as a child layer (and so not root), we still end up creating a render surface
for it due to this case:

https://cs.chromium.org/chromium/src/cc/trees/property_tree_builder.cc?sq=pac...

which, again, means we'll overwrite it with kSrcOver.

Eric set up a simple web page test case that has a div with multiply blend mode
and I believe it ended up creating a RenderPassDrawQuad, and not even a
SolidColorDrawQuad, which would presumably be what this test would be focused on
testing in any case. So we've not found a way that, in the wild, the logic this
test was aiming to validate will be needed.

[ajuma, 2017/01/06 23:47:08]

Makes sense. See also
https://cs.chromium.org/chromium/src/cc/trees/occlusion_tracker.cc?rcl=148371...
where we DCHECK that draw_blend_mode is currently always SrcOver.

-  const SkBlendMode blend_mode = SkBlendMode::kMultiply;
-
-  std::unique_ptr<RenderPass> render_pass = RenderPass::Create();
-
-  gfx::Size layer_size = gfx::Size(100, 100);
-
-  FakeImplTaskRunnerProvider task_runner_provider;
-  TestTaskGraphRunner task_graph_runner;
-  FakeLayerTreeHostImpl host_impl(&task_runner_provider, &task_graph_runner);
-  std::unique_ptr<SolidColorLayerImpl> layer =
-      SolidColorLayerImpl::Create(host_impl.active_tree(), 1);
-  layer->SetBounds(layer_size);
-  layer->set_draw_blend_mode(blend_mode);
-
-  AppendQuadsData data;
-  layer->AppendQuads(render_pass.get(), &data);
-
-  ASSERT_EQ(render_pass->quad_list.size(), 1U);
-  EXPECT_EQ(blend_mode,
-            render_pass->quad_list.front()->shared_quad_state->blend_mode);
-}
-
 TEST(SolidColorLayerImplTest, VerifyOpaqueRect) {
   gfx::Size layer_size = gfx::Size(100, 100);
   gfx::Rect visible_layer_rect = gfx::Rect(layer_size);
@@ -149,10 +132,10 @@ TEST(SolidColorLayerImplTest, VerifyOpaqueRect) {
   layer->SetBackgroundColor(SkColorSetARGBInline(255, 10, 20, 30));
   EXPECT_TRUE(layer->contents_opaque());
   {
-    std::unique_ptr<SolidColorLayerImpl> layer_impl =
-        SolidColorLayerImpl::Create(host->host_impl()->active_tree(),
-                                    layer->id());
-    layer->PushPropertiesTo(layer_impl.get());
+    DebugScopedSetImplThread scoped_impl_thread(host->GetTaskRunnerProvider());
+    host->FinishCommitOnImplThread(host->host_impl());
+    LayerImpl* layer_impl =
+        host->host_impl()->active_tree()->LayerById(layer->id());
 
     // The impl layer should call itself opaque as well.
     EXPECT_TRUE(layer_impl->contents_opaque());
@@ -175,12 +158,12 @@ TEST(SolidColorLayerImplTest, VerifyOpaqueRect) {
   layer->SetBackgroundColor(SkColorSetARGBInline(254, 10, 20, 30));
   EXPECT_FALSE(layer->contents_opaque());
   {
-    std::unique_ptr<SolidColorLayerImpl> layer_impl =
-        SolidColorLayerImpl::Create(host->host_impl()->active_tree(),
-                                    layer->id());
-    layer->PushPropertiesTo(layer_impl.get());
+    DebugScopedSetImplThread scoped_impl_thread(host->GetTaskRunnerProvider());
+    host->FinishCommitOnImplThread(host->host_impl());
+    LayerImpl* layer_impl =
+        host->host_impl()->active_tree()->LayerById(layer->id());
 
-    // The impl layer should callnot itself opaque anymore.
+    // The impl layer should not call itself opaque anymore.
     EXPECT_FALSE(layer_impl->contents_opaque());
 
     // Impl layer has 1 opacity, but the color is not opaque, so the opaque_rect