Replace LayerImpl::sorting_context_id with transform reference.

third_party/WebKit/Source/platform/graphics/CompositorMutableStateTest.cpp

 // Copyright 2016 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 "platform/graphics/CompositorMutableState.h"
 
 #include "base/message_loop/message_loop.h"
 #include "cc/test/fake_compositor_frame_sink.h"
 #include "cc/test/fake_impl_task_runner_provider.h"
 #include "cc/test/fake_layer_tree_host_impl.h"
@@ skipping 27 matching lines @@
     m_hostImpl.reset(new FakeLayerTreeHostImpl(settings, &m_taskRunnerProvider,
                                                &m_taskGraphRunner));
     m_hostImpl->SetVisible(true);
     EXPECT_TRUE(m_hostImpl->InitializeRenderer(m_compositorFrameSink.get()));
   }
 
   void SetLayerPropertiesForTesting(LayerImpl* layer) {
     layer->test_properties()->transform = gfx::Transform();
     layer->SetPosition(gfx::PointF());
     layer->SetBounds(gfx::Size(100, 100));
-    layer->Set3dSortingContextId(0);
     layer->SetDrawsContent(true);
   }
 
   FakeLayerTreeHostImpl& hostImpl() { return *m_hostImpl; }
 
   LayerImpl* rootLayer() {
     return m_hostImpl->active_tree()->root_layer_for_testing();
   }
 
  private:
@@ skipping 88 matching lines @@
   EXPECT_TRUE(mutation.isScrollLeftMutated());
   EXPECT_TRUE(mutation.isScrollTopMutated());
 
   EXPECT_EQ(0.5, mutation.opacity());
   EXPECT_EQ(zero.ToString(), gfx::Transform(mutation.transform()).ToString());
   EXPECT_EQ(1.0, mutation.scrollLeft());
   EXPECT_EQ(1.0, mutation.scrollTop());
 }
 
 }  // namespace blink