Update from https://crrev.com/316786

cc/layers/scrollbar_layer_unittest.cc

 // Copyright 2012 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 "base/containers/hash_tables.h"
 #include "cc/animation/scrollbar_animation_controller.h"
 #include "cc/layers/append_quads_data.h"
 #include "cc/layers/painted_scrollbar_layer.h"
 #include "cc/layers/painted_scrollbar_layer_impl.h"
 #include "cc/layers/scrollbar_layer_interface.h"
@@ skipping 41 matching lines @@
   } else {
     child2 = PaintedScrollbarLayer::Create(scrollbar.Pass(), child1->id());
   }
   child2->ToScrollbarLayer()->SetClipLayer(layer_tree_root->id());
   layer_tree_root->AddChild(child1);
   layer_tree_root->InsertChild(child2, reverse_order ? 0 : 1);
   host->SetRootLayer(layer_tree_root);
   return host->CommitAndCreateLayerImplTree();
 }
 
-TEST(ScrollbarLayerTest, ResolveScrollLayerPointer) {
-  FakeLayerTreeHostClient client(FakeLayerTreeHostClient::DIRECT_3D);
-  scoped_ptr<FakeLayerTreeHost> host = FakeLayerTreeHost::Create(&client);
+class FakeResourceTrackingLayerTreeHost : public FakeLayerTreeHost {
+ public:
+  FakeResourceTrackingLayerTreeHost(FakeLayerTreeHostClient* client,
+                                    const LayerTreeSettings& settings)
+      : FakeLayerTreeHost(client, settings),
+        next_id_(1),
+        total_ui_resource_created_(0),
+        total_ui_resource_deleted_(0) {
+    InitializeSingleThreaded(client, base::MessageLoopProxy::current(),
+                             nullptr);
+  }
+
+  UIResourceId CreateUIResource(UIResourceClient* content) override {
+    total_ui_resource_created_++;
+    UIResourceId nid = next_id_++;
+    ui_resource_bitmap_map_.insert(
+        std::make_pair(nid, content->GetBitmap(nid, false)));
+    return nid;
+  }
+
+  // Deletes a UI resource.  May safely be called more than once.
+  void DeleteUIResource(UIResourceId id) override {
+    UIResourceBitmapMap::iterator iter = ui_resource_bitmap_map_.find(id);
+    if (iter != ui_resource_bitmap_map_.end()) {
+      ui_resource_bitmap_map_.erase(iter);
+      total_ui_resource_deleted_++;
+    }
+  }
+
+  size_t UIResourceCount() { return ui_resource_bitmap_map_.size(); }
+  int TotalUIResourceDeleted() { return total_ui_resource_deleted_; }
+  int TotalUIResourceCreated() { return total_ui_resource_created_; }
+
+  gfx::Size ui_resource_size(UIResourceId id) {
+    UIResourceBitmapMap::iterator iter = ui_resource_bitmap_map_.find(id);
+    if (iter != ui_resource_bitmap_map_.end())
+      return iter->second.GetSize();
+    return gfx::Size();
+  }
+
+  UIResourceBitmap* ui_resource_bitmap(UIResourceId id) {
+    UIResourceBitmapMap::iterator iter = ui_resource_bitmap_map_.find(id);
+    if (iter != ui_resource_bitmap_map_.end())
+      return &iter->second;
+    return nullptr;
+  }
+
+ private:
+  using UIResourceBitmapMap = base::hash_map<UIResourceId, UIResourceBitmap>;
+  UIResourceBitmapMap ui_resource_bitmap_map_;
+
+  int next_id_;
+  int total_ui_resource_created_;
+  int total_ui_resource_deleted_;
+};
+
+class ScrollbarLayerTest : public testing::Test {
+ public:
+  ScrollbarLayerTest() : fake_client_(FakeLayerTreeHostClient::DIRECT_3D) {
+    layer_tree_settings_.single_thread_proxy_scheduler = false;
+    layer_tree_host_.reset(new FakeResourceTrackingLayerTreeHost(
+        &fake_client_, layer_tree_settings_));
+    fake_client_.SetLayerTreeHost(layer_tree_host_.get());
+    // Force output surface creation for renderer capabilities.
+    layer_tree_host_->Composite(base::TimeTicks());
+    EXPECT_FALSE(layer_tree_host_->output_surface_lost());
+  }
+
+ protected:
+  FakeLayerTreeHostClient fake_client_;
+  LayerTreeSettings layer_tree_settings_;
+  scoped_ptr<FakeResourceTrackingLayerTreeHost> layer_tree_host_;
+};
+
+TEST_F(ScrollbarLayerTest, ResolveScrollLayerPointer) {
   scoped_ptr<Scrollbar> scrollbar(new FakeScrollbar);
   LayerImpl* layer_impl_tree_root = LayerImplForScrollAreaAndScrollbar(
-      host.get(), scrollbar.Pass(), false, false, 0, 0);
+      layer_tree_host_.get(), scrollbar.Pass(), false, false, 0, 0);
 
   LayerImpl* cc_child1 = layer_impl_tree_root->children()[0];
   PaintedScrollbarLayerImpl* cc_child2 =
       static_cast<PaintedScrollbarLayerImpl*>(
           layer_impl_tree_root->children()[1]);
 
   EXPECT_EQ(cc_child1->scrollbars()->size(), 1UL);
   EXPECT_EQ(*(cc_child1->scrollbars()->begin()), cc_child2);
 }
 
-TEST(ScrollbarLayerTest, ResolveScrollLayerPointer_ReverseOrder) {
-  FakeLayerTreeHostClient client(FakeLayerTreeHostClient::DIRECT_3D);
-  scoped_ptr<FakeLayerTreeHost> host = FakeLayerTreeHost::Create(&client);
+TEST_F(ScrollbarLayerTest, ResolveScrollLayerPointer_ReverseOrder) {
   scoped_ptr<Scrollbar> scrollbar(new FakeScrollbar);
   LayerImpl* layer_impl_tree_root = LayerImplForScrollAreaAndScrollbar(
-      host.get(), scrollbar.Pass(), true, false, 0, 0);
+      layer_tree_host_.get(), scrollbar.Pass(), true, false, 0, 0);
 
   PaintedScrollbarLayerImpl* cc_child1 =
       static_cast<PaintedScrollbarLayerImpl*>(
           layer_impl_tree_root->children()[0]);
   LayerImpl* cc_child2 = layer_impl_tree_root->children()[1];
 
   EXPECT_EQ(cc_child2->scrollbars()->size(), 1UL);
   EXPECT_EQ(*(cc_child2->scrollbars()->begin()), cc_child1);
 }
 
-TEST(ScrollbarLayerTest, ShouldScrollNonOverlayOnMainThread) {
-  FakeLayerTreeHostClient client(FakeLayerTreeHostClient::DIRECT_3D);
-  scoped_ptr<FakeLayerTreeHost> host = FakeLayerTreeHost::Create(&client);
-
+TEST_F(ScrollbarLayerTest, ShouldScrollNonOverlayOnMainThread) {
   // Create and attach a non-overlay scrollbar.
   scoped_ptr<Scrollbar> scrollbar(new FakeScrollbar);
   LayerImpl* layer_impl_tree_root = LayerImplForScrollAreaAndScrollbar(
-      host.get(), scrollbar.Pass(), false, false, 0, 0);
+      layer_tree_host_.get(), scrollbar.Pass(), false, false, 0, 0);
   PaintedScrollbarLayerImpl* scrollbar_layer_impl =
       static_cast<PaintedScrollbarLayerImpl*>(
           layer_impl_tree_root->children()[1]);
 
   // When the scrollbar is not an overlay scrollbar, the scroll should be
   // responded to on the main thread as the compositor does not yet implement
   // scrollbar scrolling.
   EXPECT_EQ(InputHandler::ScrollOnMainThread,
             scrollbar_layer_impl->TryScroll(
                 gfx::Point(0, 0), InputHandler::Gesture, ScrollBlocksOnNone));
 
   // Create and attach an overlay scrollbar.
   scrollbar.reset(new FakeScrollbar(false, false, true));
 
   layer_impl_tree_root = LayerImplForScrollAreaAndScrollbar(
-      host.get(), scrollbar.Pass(), false, false, 0, 0);
+      layer_tree_host_.get(), scrollbar.Pass(), false, false, 0, 0);
   scrollbar_layer_impl = static_cast<PaintedScrollbarLayerImpl*>(
       layer_impl_tree_root->children()[1]);
 
   // The user shouldn't be able to drag an overlay scrollbar and the scroll
   // may be handled in the compositor.
   EXPECT_EQ(InputHandler::ScrollIgnored,
             scrollbar_layer_impl->TryScroll(
                 gfx::Point(0, 0), InputHandler::Gesture, ScrollBlocksOnNone));
 }
 
-TEST(PaintedScrollbarLayerTest, ScrollOffsetSynchronization) {
-  FakeLayerTreeHostClient client(FakeLayerTreeHostClient::DIRECT_3D);
-  scoped_ptr<FakeLayerTreeHost> host = FakeLayerTreeHost::Create(&client);
-
+TEST_F(ScrollbarLayerTest, ScrollOffsetSynchronization) {
   scoped_ptr<Scrollbar> scrollbar(new FakeScrollbar);
   scoped_refptr<Layer> layer_tree_root = Layer::Create();
   scoped_refptr<Layer> scroll_layer = Layer::Create();
   scoped_refptr<Layer> content_layer = Layer::Create();
   scoped_refptr<Layer> scrollbar_layer =
       PaintedScrollbarLayer::Create(scrollbar.Pass(), layer_tree_root->id());
 
   // Choose bounds to give max_scroll_offset = (30, 50).
   layer_tree_root->SetBounds(gfx::Size(70, 150));
   scroll_layer->SetScrollClipLayerId(layer_tree_root->id());
   scroll_layer->SetScrollOffset(gfx::ScrollOffset(10, 20));
   scroll_layer->SetBounds(gfx::Size(100, 200));
   content_layer->SetBounds(gfx::Size(100, 200));
 
-  host->SetRootLayer(layer_tree_root);
+  layer_tree_host_->SetRootLayer(layer_tree_root);
   layer_tree_root->AddChild(scroll_layer);
   scroll_layer->AddChild(content_layer);
   layer_tree_root->AddChild(scrollbar_layer);
   scrollbar_layer->ToScrollbarLayer()->SetScrollLayer(scroll_layer->id());
   scrollbar_layer->ToScrollbarLayer()->SetClipLayer(layer_tree_root->id());
 
   layer_tree_root->SavePaintProperties();
   content_layer->SavePaintProperties();
 
-  LayerImpl* layer_impl_tree_root = host->CommitAndCreateLayerImplTree();
+  LayerImpl* layer_impl_tree_root =
+      layer_tree_host_->CommitAndCreateLayerImplTree();
 
   ScrollbarLayerImplBase* cc_scrollbar_layer =
       static_cast<PaintedScrollbarLayerImpl*>(
           layer_impl_tree_root->children()[1]);
 
   EXPECT_EQ(10.f, cc_scrollbar_layer->current_pos());
   EXPECT_EQ(30, cc_scrollbar_layer->maximum());
 
   layer_tree_root->SetBounds(gfx::Size(700, 1500));
   layer_tree_root->SavePaintProperties();
   scroll_layer->SetBounds(gfx::Size(1000, 2000));
   scroll_layer->SetScrollOffset(gfx::ScrollOffset(100, 200));
   scroll_layer->SavePaintProperties();
   content_layer->SetBounds(gfx::Size(1000, 2000));
   content_layer->SavePaintProperties();
 
   ScrollbarAnimationController* scrollbar_controller =
       layer_impl_tree_root->scrollbar_animation_controller();
-  layer_impl_tree_root = host->CommitAndCreateLayerImplTree();
+  layer_impl_tree_root = layer_tree_host_->CommitAndCreateLayerImplTree();
   EXPECT_EQ(scrollbar_controller,
             layer_impl_tree_root->scrollbar_animation_controller());
 
   EXPECT_EQ(100.f, cc_scrollbar_layer->current_pos());
   EXPECT_EQ(300, cc_scrollbar_layer->maximum());
 
   LayerImpl* scroll_layer_impl = layer_impl_tree_root->children()[0];
   scroll_layer_impl->ScrollBy(gfx::Vector2d(12, 34));
 
   EXPECT_EQ(112.f, cc_scrollbar_layer->current_pos());
   EXPECT_EQ(300, cc_scrollbar_layer->maximum());
 }
 
-#define UPDATE_AND_EXTRACT_LAYER_POINTERS()                         \
-  do {                                                              \
-    scrollbar_layer->UpdateThumbAndTrackGeometry();                 \
-    root_clip_layer_impl = host->CommitAndCreateLayerImplTree();    \
-    root_layer_impl = root_clip_layer_impl->children()[0];          \
-    scrollbar_layer_impl = static_cast<PaintedScrollbarLayerImpl*>( \
-        root_layer_impl->children()[1]);                            \
-    scrollbar_layer_impl->ScrollbarParametersDidChange(false);      \
+#define UPDATE_AND_EXTRACT_LAYER_POINTERS()                                  \
+  do {                                                                       \
+    scrollbar_layer->UpdateInternalContentScale();                           \
+    scrollbar_layer->UpdateThumbAndTrackGeometry();                          \
+    root_clip_layer_impl = layer_tree_host_->CommitAndCreateLayerImplTree(); \
+    root_layer_impl = root_clip_layer_impl->children()[0];                   \
+    scrollbar_layer_impl = static_cast<PaintedScrollbarLayerImpl*>(          \
+        root_layer_impl->children()[1]);                                     \
+    scrollbar_layer_impl->ScrollbarParametersDidChange(false);               \
   } while (false)
 
-TEST(ScrollbarLayerTest, UpdatePropertiesOfScrollBarWhenThumbRemoved) {
-  FakeLayerTreeHostClient client(FakeLayerTreeHostClient::DIRECT_3D);
-  scoped_ptr<FakeLayerTreeHost> host = FakeLayerTreeHost::Create(&client);
+TEST_F(ScrollbarLayerTest, UpdatePropertiesOfScrollBarWhenThumbRemoved) {
   scoped_refptr<Layer> root_clip_layer = Layer::Create();
   scoped_refptr<Layer> root_layer = Layer::Create();
   scoped_refptr<Layer> content_layer = Layer::Create();
   scoped_refptr<FakePaintedScrollbarLayer> scrollbar_layer =
       FakePaintedScrollbarLayer::Create(false, true, root_layer->id());
 
   root_layer->SetScrollClipLayerId(root_clip_layer->id());
   // Give the root-clip a size that will result in MaxScrollOffset = (80, 0).
   root_clip_layer->SetBounds(gfx::Size(20, 50));
   root_layer->SetBounds(gfx::Size(100, 50));
   content_layer->SetBounds(gfx::Size(100, 50));
 
-  host->SetRootLayer(root_clip_layer);
+  layer_tree_host_->SetRootLayer(root_clip_layer);
   root_clip_layer->AddChild(root_layer);
   root_layer->AddChild(content_layer);
   root_layer->AddChild(scrollbar_layer);
 
   root_layer->SetScrollOffset(gfx::ScrollOffset(0, 0));
   scrollbar_layer->SetBounds(gfx::Size(70, 10));
   scrollbar_layer->SetScrollLayer(root_layer->id());
   scrollbar_layer->SetClipLayer(root_clip_layer->id());
   scrollbar_layer->fake_scrollbar()->set_location(gfx::Point(20, 10));
   scrollbar_layer->fake_scrollbar()->set_track_rect(gfx::Rect(30, 10, 50, 10));
   scrollbar_layer->fake_scrollbar()->set_thumb_thickness(10);
   scrollbar_layer->fake_scrollbar()->set_thumb_length(4);
-
-  scrollbar_layer->UpdateThumbAndTrackGeometry();
   LayerImpl* root_clip_layer_impl = nullptr;
   LayerImpl* root_layer_impl = nullptr;
   PaintedScrollbarLayerImpl* scrollbar_layer_impl = nullptr;
 
   UPDATE_AND_EXTRACT_LAYER_POINTERS();
   EXPECT_EQ(gfx::Rect(10, 0, 4, 10).ToString(),
             scrollbar_layer_impl->ComputeThumbQuadRect().ToString());
 
   scrollbar_layer->fake_scrollbar()->set_has_thumb(false);
 
   UPDATE_AND_EXTRACT_LAYER_POINTERS();
   EXPECT_EQ(gfx::Rect(10, 0, 0, 0).ToString(),
             scrollbar_layer_impl->ComputeThumbQuadRect().ToString());
 }
 
-TEST(ScrollbarLayerTest, ThumbRect) {
-  FakeLayerTreeHostClient client(FakeLayerTreeHostClient::DIRECT_3D);
-  scoped_ptr<FakeLayerTreeHost> host = FakeLayerTreeHost::Create(&client);
+TEST_F(ScrollbarLayerTest, ThumbRect) {
   scoped_refptr<Layer> root_clip_layer = Layer::Create();
   scoped_refptr<Layer> root_layer = Layer::Create();
   scoped_refptr<Layer> content_layer = Layer::Create();
   scoped_refptr<FakePaintedScrollbarLayer> scrollbar_layer =
       FakePaintedScrollbarLayer::Create(false, true, root_layer->id());
 
   root_layer->SetScrollClipLayerId(root_clip_layer->id());
   // Give the root-clip a size that will result in MaxScrollOffset = (80, 0).
   root_clip_layer->SetBounds(gfx::Size(20, 50));
   root_layer->SetBounds(gfx::Size(100, 50));
   content_layer->SetBounds(gfx::Size(100, 50));
 
-  host->SetRootLayer(root_clip_layer);
+  layer_tree_host_->SetRootLayer(root_clip_layer);
   root_clip_layer->AddChild(root_layer);
   root_layer->AddChild(content_layer);
   root_layer->AddChild(scrollbar_layer);
 
   root_layer->SetScrollOffset(gfx::ScrollOffset(0, 0));
   scrollbar_layer->SetBounds(gfx::Size(70, 10));
   scrollbar_layer->SetScrollLayer(root_layer->id());
   scrollbar_layer->SetClipLayer(root_clip_layer->id());
   scrollbar_layer->fake_scrollbar()->set_location(gfx::Point(20, 10));
   scrollbar_layer->fake_scrollbar()->set_track_rect(gfx::Rect(30, 10, 50, 10));
   scrollbar_layer->fake_scrollbar()->set_thumb_thickness(10);
   scrollbar_layer->fake_scrollbar()->set_thumb_length(4);
-  scrollbar_layer->UpdateThumbAndTrackGeometry();
   LayerImpl* root_clip_layer_impl = nullptr;
   LayerImpl* root_layer_impl = nullptr;
   PaintedScrollbarLayerImpl* scrollbar_layer_impl = nullptr;
 
   // Thumb is at the edge of the scrollbar (should be inset to
   // the start of the track within the scrollbar layer's
   // position).
   UPDATE_AND_EXTRACT_LAYER_POINTERS();
   EXPECT_EQ(gfx::Rect(10, 0, 4, 10).ToString(),
             scrollbar_layer_impl->ComputeThumbQuadRect().ToString());
@@ skipping 32 matching lines @@
   // Shrink the track in the non-scrolling dimension so that it only covers the
   // middle third of the scrollbar layer (this does not affect the thumb
   // position).
   scrollbar_layer->fake_scrollbar()->set_track_rect(gfx::Rect(30, 12, 50, 6));
 
   UPDATE_AND_EXTRACT_LAYER_POINTERS();
   EXPECT_EQ(gfx::Rect(44, 0, 6, 4).ToString(),
             scrollbar_layer_impl->ComputeThumbQuadRect().ToString());
 }
 
-TEST(ScrollbarLayerTest, SolidColorDrawQuads) {
+TEST_F(ScrollbarLayerTest, SolidColorDrawQuads) {
   const int kThumbThickness = 3;
   const int kTrackStart = 1;
   const int kTrackLength = 100;
 
-  FakeLayerTreeHostClient client(FakeLayerTreeHostClient::DIRECT_3D);
-  LayerTreeSettings layer_tree_settings;
-  scoped_ptr<FakeLayerTreeHost> host =
-      FakeLayerTreeHost::Create(&client, layer_tree_settings);
-
   scoped_ptr<Scrollbar> scrollbar(new FakeScrollbar(false, true, true));
   LayerImpl* layer_impl_tree_root = LayerImplForScrollAreaAndScrollbar(
-      host.get(), scrollbar.Pass(), false, true, kThumbThickness, kTrackStart);
+      layer_tree_host_.get(), scrollbar.Pass(), false, true, kThumbThickness,
+      kTrackStart);
   ScrollbarLayerImplBase* scrollbar_layer_impl =
       static_cast<SolidColorScrollbarLayerImpl*>(
           layer_impl_tree_root->children()[1]);
   scrollbar_layer_impl->SetBounds(gfx::Size(kTrackLength, kThumbThickness));
   scrollbar_layer_impl->SetCurrentPos(10.f);
   scrollbar_layer_impl->SetMaximum(100);
   scrollbar_layer_impl->SetVisibleToTotalLengthRatio(0.4f);
 
   // Thickness should be overridden to 3.
   {
     scoped_ptr<RenderPass> render_pass = RenderPass::Create();
     AppendQuadsData data;
-    scrollbar_layer_impl->AppendQuads(render_pass.get(), Occlusion(), &data);
+    scrollbar_layer_impl->AppendQuads(render_pass.get(), &data);
 
     const QuadList& quads = render_pass->quad_list;
     ASSERT_EQ(1u, quads.size());
     EXPECT_EQ(DrawQuad::SOLID_COLOR, quads.front()->material);
     EXPECT_EQ(gfx::Rect(6, 0, 39, 3), quads.front()->rect);
   }
 
   // Contents scale should scale the draw quad.
   scrollbar_layer_impl->draw_properties().contents_scale_x = 2.f;
   scrollbar_layer_impl->draw_properties().contents_scale_y = 2.f;
   {
     scoped_ptr<RenderPass> render_pass = RenderPass::Create();
     AppendQuadsData data;
-    scrollbar_layer_impl->AppendQuads(render_pass.get(), Occlusion(), &data);
+    scrollbar_layer_impl->AppendQuads(render_pass.get(), &data);
 
     const QuadList& quads = render_pass->quad_list;
     ASSERT_EQ(1u, quads.size());
     EXPECT_EQ(DrawQuad::SOLID_COLOR, quads.front()->material);
     EXPECT_EQ(gfx::Rect(12, 0, 78, 6), quads.front()->rect);
   }
   scrollbar_layer_impl->draw_properties().contents_scale_x = 1.f;
   scrollbar_layer_impl->draw_properties().contents_scale_y = 1.f;
 
   // For solid color scrollbars, position and size should reflect the
   // current viewport state.
   scrollbar_layer_impl->SetVisibleToTotalLengthRatio(0.2f);
   {
     scoped_ptr<RenderPass> render_pass = RenderPass::Create();
     AppendQuadsData data;
-    scrollbar_layer_impl->AppendQuads(render_pass.get(), Occlusion(), &data);
+    scrollbar_layer_impl->AppendQuads(render_pass.get(), &data);
 
     const QuadList& quads = render_pass->quad_list;
     ASSERT_EQ(1u, quads.size());
     EXPECT_EQ(DrawQuad::SOLID_COLOR, quads.front()->material);
     EXPECT_EQ(gfx::Rect(8, 0, 19, 3), quads.front()->rect);
   }
 
   // We shouldn't attempt div-by-zero when the maximum is zero.
   scrollbar_layer_impl->SetCurrentPos(0.f);
   scrollbar_layer_impl->SetMaximum(0);
   {
     scoped_ptr<RenderPass> render_pass = RenderPass::Create();
     AppendQuadsData data;
-    scrollbar_layer_impl->AppendQuads(render_pass.get(), Occlusion(), &data);
+    scrollbar_layer_impl->AppendQuads(render_pass.get(), &data);
 
     const QuadList& quads = render_pass->quad_list;
     ASSERT_EQ(1u, quads.size());
     EXPECT_EQ(DrawQuad::SOLID_COLOR, quads.front()->material);
     EXPECT_EQ(gfx::Rect(1, 0, 19, 3), quads.front()->rect);
   }
 }
 
-TEST(ScrollbarLayerTest, LayerDrivenSolidColorDrawQuads) {
+TEST_F(ScrollbarLayerTest, LayerDrivenSolidColorDrawQuads) {
   const int kThumbThickness = 3;
   const int kTrackStart = 0;
   const int kTrackLength = 10;
 
-  FakeLayerTreeHostClient client(FakeLayerTreeHostClient::DIRECT_3D);
-  LayerTreeSettings layer_tree_settings;
-  scoped_ptr<FakeLayerTreeHost> host =
-      FakeLayerTreeHost::Create(&client, layer_tree_settings);
-
   scoped_ptr<Scrollbar> scrollbar(new FakeScrollbar(false, true, true));
 
   {
     scoped_refptr<Layer> layer_tree_root = Layer::Create();
     scoped_refptr<Layer> scroll_layer = Layer::Create();
     scroll_layer->SetScrollClipLayerId(layer_tree_root->id());
     scoped_refptr<Layer> child1 = Layer::Create();
     scoped_refptr<Layer> child2;
     const bool kIsLeftSideVerticalScrollbar = false;
     child2 = SolidColorScrollbarLayer::Create(scrollbar->Orientation(),
                                               kThumbThickness,
                                               kTrackStart,
                                               kIsLeftSideVerticalScrollbar,
                                               child1->id());
     child2->ToScrollbarLayer()->SetScrollLayer(scroll_layer->id());
     child2->ToScrollbarLayer()->SetClipLayer(layer_tree_root->id());
     scroll_layer->AddChild(child1);
     scroll_layer->InsertChild(child2, 1);
     layer_tree_root->AddChild(scroll_layer);
-    host->SetRootLayer(layer_tree_root);
+    layer_tree_host_->SetRootLayer(layer_tree_root);
   }
-  LayerImpl* layer_impl_tree_root = host->CommitAndCreateLayerImplTree();
+  LayerImpl* layer_impl_tree_root =
+      layer_tree_host_->CommitAndCreateLayerImplTree();
   LayerImpl* scroll_layer_impl = layer_impl_tree_root->children()[0];
 
   ScrollbarLayerImplBase* scrollbar_layer_impl =
       static_cast<PaintedScrollbarLayerImpl*>(scroll_layer_impl->children()[1]);
 
   // Choose layer bounds to give max_scroll_offset = (8, 8).
   layer_impl_tree_root->SetBounds(gfx::Size(2, 2));
   scroll_layer_impl->SetBounds(gfx::Size(10, 10));
   scroll_layer_impl->ScrollBy(gfx::Vector2dF(4.f, 0.f));
 
   scrollbar_layer_impl->SetBounds(gfx::Size(kTrackLength, kThumbThickness));
   scrollbar_layer_impl->SetCurrentPos(4.f);
   scrollbar_layer_impl->SetMaximum(8);
 
   {
     scoped_ptr<RenderPass> render_pass = RenderPass::Create();
 
     AppendQuadsData data;
-    scrollbar_layer_impl->AppendQuads(render_pass.get(), Occlusion(), &data);
+    scrollbar_layer_impl->AppendQuads(render_pass.get(), &data);
 
     const QuadList& quads = render_pass->quad_list;
     ASSERT_EQ(1u, quads.size());
     EXPECT_EQ(DrawQuad::SOLID_COLOR, quads.front()->material);
     EXPECT_EQ(gfx::Rect(3, 0, 3, 3), quads.front()->rect);
   }
 }
 
 class ScrollbarLayerSolidColorThumbTest : public testing::Test {
  public:
@@ skipping 107 matching lines @@
   void BeginTest() override {
     scroll_layer_ = Layer::Create();
     layer_tree_host()->root_layer()->AddChild(scroll_layer_);
 
     scoped_ptr<Scrollbar> scrollbar(new FakeScrollbar);
     scrollbar_layer_ =
         PaintedScrollbarLayer::Create(scrollbar.Pass(), scroll_layer_->id());
     scrollbar_layer_->SetScrollLayer(scroll_layer_->id());
     scrollbar_layer_->SetLayerTreeHost(layer_tree_host());
     scrollbar_layer_->SetBounds(bounds_);
+    scrollbar_layer_->SetIsDrawable(true);
     layer_tree_host()->root_layer()->AddChild(scrollbar_layer_);
 
     PostSetNeedsCommitToMainThread();
   }
 
   void DidCommitAndDrawFrame() override {
     const int kMaxTextureSize =
         layer_tree_host()->GetRendererCapabilities().max_texture_size;
 
     // Check first that we're actually testing something.
     EXPECT_GT(scrollbar_layer_->bounds().width(), kMaxTextureSize);
 
-    EXPECT_EQ(scrollbar_layer_->content_bounds().width(),
+    EXPECT_EQ(scrollbar_layer_->internal_content_bounds().width(),
               kMaxTextureSize - 1);
-    EXPECT_EQ(scrollbar_layer_->content_bounds().height(),
+    EXPECT_EQ(scrollbar_layer_->internal_content_bounds().height(),
               kMaxTextureSize - 1);
 
     EndTest();
   }
 
   void AfterTest() override {}
 
  private:
   scoped_refptr<PaintedScrollbarLayer> scrollbar_layer_;
   scoped_refptr<Layer> scroll_layer_;
@@ skipping 11 matching lines @@
 
 TEST_F(ScrollbarLayerTestMaxTextureSize, DelegatingRenderer) {
   scoped_ptr<TestWebGraphicsContext3D> context =
       TestWebGraphicsContext3D::Create();
   int max_size = 0;
   context->getIntegerv(GL_MAX_TEXTURE_SIZE, &max_size);
   SetScrollbarBounds(gfx::Size(max_size + 100, max_size + 100));
   RunTest(true, true, true);
 }
 
-class FakeLayerTreeHost : public LayerTreeHost {
+class ScrollbarLayerTestResourceCreationAndRelease : public ScrollbarLayerTest {
  public:
-  FakeLayerTreeHost(FakeLayerTreeHostClient* client,
-                    const LayerTreeSettings& settings)
-      : LayerTreeHost(client, nullptr, nullptr, settings),
-        next_id_(1),
-        total_ui_resource_created_(0),
-        total_ui_resource_deleted_(0) {
-    InitializeSingleThreaded(client,
-                             base::MessageLoopProxy::current(),
-                             nullptr);
-  }
-
-  UIResourceId CreateUIResource(UIResourceClient* content) override {
-    total_ui_resource_created_++;
-    UIResourceId nid = next_id_++;
-    ui_resource_bitmap_map_.insert(
-        std::make_pair(nid, content->GetBitmap(nid, false)));
-    return nid;
-  }
-
-  // Deletes a UI resource.  May safely be called more than once.
-  void DeleteUIResource(UIResourceId id) override {
-    UIResourceBitmapMap::iterator iter = ui_resource_bitmap_map_.find(id);
-    if (iter != ui_resource_bitmap_map_.end()) {
-      ui_resource_bitmap_map_.erase(iter);
-      total_ui_resource_deleted_++;
-    }
-  }
-
-  size_t UIResourceCount() { return ui_resource_bitmap_map_.size(); }
-  int TotalUIResourceDeleted() { return total_ui_resource_deleted_; }
-  int TotalUIResourceCreated() { return total_ui_resource_created_; }
-
-  gfx::Size ui_resource_size(UIResourceId id) {
-    UIResourceBitmapMap::iterator iter = ui_resource_bitmap_map_.find(id);
-    if (iter != ui_resource_bitmap_map_.end())
-      return iter->second.GetSize();
-    return gfx::Size();
-  }
-
-  UIResourceBitmap* ui_resource_bitmap(UIResourceId id) {
-    UIResourceBitmapMap::iterator iter = ui_resource_bitmap_map_.find(id);
-    if (iter != ui_resource_bitmap_map_.end())
-      return &iter->second;
-    return nullptr;
-  }
-
- private:
-  typedef base::hash_map<UIResourceId, UIResourceBitmap>
-      UIResourceBitmapMap;
-  UIResourceBitmapMap ui_resource_bitmap_map_;
-
-  int next_id_;
-  int total_ui_resource_created_;
-  int total_ui_resource_deleted_;
-};
-
-class ScrollbarLayerTestResourceCreationAndRelease : public testing::Test {
- public:
-  ScrollbarLayerTestResourceCreationAndRelease()
-      : fake_client_(FakeLayerTreeHostClient::DIRECT_3D) {}
-
   void TestResourceUpload(int num_updates,
                           size_t expected_resources,
                           int expected_created,
                           int expected_deleted,
                           bool use_solid_color_scrollbar) {
-    layer_tree_host_.reset(
-        new FakeLayerTreeHost(&fake_client_, layer_tree_settings_));
-
     scoped_ptr<Scrollbar> scrollbar(new FakeScrollbar(false, true, false));
     scoped_refptr<Layer> layer_tree_root = Layer::Create();
     scoped_refptr<Layer> content_layer = Layer::Create();
     scoped_refptr<Layer> scrollbar_layer;
     if (use_solid_color_scrollbar) {
       const int kThumbThickness = 3;
       const int kTrackStart = 0;
       const bool kIsLeftSideVerticalScrollbar = false;
       scrollbar_layer =
           SolidColorScrollbarLayer::Create(scrollbar->Orientation(),
@@ skipping 34 matching lines @@
 
     // A non-solid-color scrollbar should have requested two textures.
     EXPECT_EQ(expected_resources, layer_tree_host_->UIResourceCount());
     EXPECT_EQ(expected_created, layer_tree_host_->TotalUIResourceCreated());
     EXPECT_EQ(expected_deleted, layer_tree_host_->TotalUIResourceDeleted());
 
     testing::Mock::VerifyAndClearExpectations(layer_tree_host_.get());
 
     scrollbar_layer->ClearRenderSurface();
   }
-
- protected:
-  FakeLayerTreeHostClient fake_client_;
-  LayerTreeSettings layer_tree_settings_;
-  scoped_ptr<FakeLayerTreeHost> layer_tree_host_;
 };
 
 TEST_F(ScrollbarLayerTestResourceCreationAndRelease, ResourceUpload) {
   bool use_solid_color_scrollbars = false;
   TestResourceUpload(0, 0, 0, 0, use_solid_color_scrollbars);
   int num_updates[3] = {1, 5, 10};
+  int created = 0;
+  int deleted = 0;
   for (int j = 0; j < 3; j++) {
-    TestResourceUpload(num_updates[j],
-                       2,
-                       num_updates[j] * 2,
-                       (num_updates[j] - 1) * 2,
+    created += num_updates[j] * 2;
+    deleted = created - 2;
+    TestResourceUpload(num_updates[j], 2, created, deleted,
                        use_solid_color_scrollbars);
   }
 }
 
 TEST_F(ScrollbarLayerTestResourceCreationAndRelease,
        SolidColorNoResourceUpload) {
   bool use_solid_color_scrollbars = true;
   TestResourceUpload(0, 0, 0, 0, use_solid_color_scrollbars);
   TestResourceUpload(1, 0, 0, 0, use_solid_color_scrollbars);
 }
 
 TEST_F(ScrollbarLayerTestResourceCreationAndRelease, TestResourceUpdate) {
-  FakeLayerTreeHostClient fake_client_(FakeLayerTreeHostClient::DIRECT_3D);
-  LayerTreeSettings layer_tree_settings_;
-  scoped_ptr<FakeLayerTreeHost> layer_tree_host_;
-
-  layer_tree_host_.reset(
-      new FakeLayerTreeHost(&fake_client_, layer_tree_settings_));
-
   gfx::Point scrollbar_location(0, 185);
   scoped_refptr<Layer> layer_tree_root = Layer::Create();
   scoped_refptr<Layer> content_layer = Layer::Create();
   scoped_refptr<FakePaintedScrollbarLayer> scrollbar_layer =
       FakePaintedScrollbarLayer::Create(false, true, layer_tree_root->id());
 
   layer_tree_root->AddChild(content_layer);
   layer_tree_root->AddChild(scrollbar_layer);
 
   layer_tree_host_->SetRootLayer(layer_tree_root);
@@ skipping 114 matching lines @@
   EXPECT_NE(0, scrollbar_layer->track_resource_id());
   EXPECT_EQ(0, scrollbar_layer->thumb_resource_id());
   EXPECT_EQ(resource_count, layer_tree_host_->UIResourceCount());
   EXPECT_EQ(expected_created, layer_tree_host_->TotalUIResourceCreated());
   EXPECT_EQ(expected_deleted, layer_tree_host_->TotalUIResourceDeleted());
 
   testing::Mock::VerifyAndClearExpectations(layer_tree_host_.get());
   scrollbar_layer->ClearRenderSurface();
 }
 
-class ScaledScrollbarLayerTestResourceCreation : public testing::Test {
+class ScaledScrollbarLayerTestResourceCreation : public ScrollbarLayerTest {
  public:
-  ScaledScrollbarLayerTestResourceCreation()
-      : fake_client_(FakeLayerTreeHostClient::DIRECT_3D) {}
-
   void TestResourceUpload(const float test_scale) {
-    layer_tree_host_.reset(
-        new FakeLayerTreeHost(&fake_client_, layer_tree_settings_));
-
     gfx::Point scrollbar_location(0, 185);
     scoped_refptr<Layer> layer_tree_root = Layer::Create();
     scoped_refptr<Layer> content_layer = Layer::Create();
     scoped_refptr<FakePaintedScrollbarLayer> scrollbar_layer =
         FakePaintedScrollbarLayer::Create(false, true, layer_tree_root->id());
 
     layer_tree_root->AddChild(content_layer);
     layer_tree_root->AddChild(scrollbar_layer);
 
     layer_tree_host_->SetRootLayer(layer_tree_root);
@@ skipping 29 matching lines @@
     scrollbar_layer->Update(&queue, &occlusion_tracker);
 
     // Verify that we have not generated any content uploads that are larger
     // than their destination textures.
 
     gfx::Size track_size = layer_tree_host_->ui_resource_size(
         scrollbar_layer->track_resource_id());
     gfx::Size thumb_size = layer_tree_host_->ui_resource_size(
         scrollbar_layer->thumb_resource_id());
 
-    EXPECT_LE(track_size.width(), scrollbar_layer->content_bounds().width());
-    EXPECT_LE(track_size.height(), scrollbar_layer->content_bounds().height());
-    EXPECT_LE(thumb_size.width(), scrollbar_layer->content_bounds().width());
-    EXPECT_LE(thumb_size.height(), scrollbar_layer->content_bounds().height());
+    EXPECT_LE(track_size.width(),
+              scrollbar_layer->internal_content_bounds().width());
+    EXPECT_LE(track_size.height(),
+              scrollbar_layer->internal_content_bounds().height());
+    EXPECT_LE(thumb_size.width(),
+              scrollbar_layer->internal_content_bounds().width());
+    EXPECT_LE(thumb_size.height(),
+              scrollbar_layer->internal_content_bounds().height());
 
     testing::Mock::VerifyAndClearExpectations(layer_tree_host_.get());
 
     scrollbar_layer->ClearRenderSurface();
   }
-
- protected:
-  FakeLayerTreeHostClient fake_client_;
-  LayerTreeSettings layer_tree_settings_;
-  scoped_ptr<FakeLayerTreeHost> layer_tree_host_;
 };
 
 TEST_F(ScaledScrollbarLayerTestResourceCreation, ScaledResourceUpload) {
   // Pick a test scale that moves the scrollbar's (non-zero) position to
   // a non-pixel-aligned location.
   TestResourceUpload(.041f);
   TestResourceUpload(1.41f);
   TestResourceUpload(4.1f);
 }
 
-class ScaledScrollbarLayerTestScaledRasterization : public testing::Test {
+class ScaledScrollbarLayerTestScaledRasterization : public ScrollbarLayerTest {
  public:
-  ScaledScrollbarLayerTestScaledRasterization()
-      : fake_client_(FakeLayerTreeHostClient::DIRECT_3D) {}
-
   void TestScale(const gfx::Rect scrollbar_rect, const float test_scale) {
-    layer_tree_host_.reset(
-        new FakeLayerTreeHost(&fake_client_, layer_tree_settings_));
-
     bool paint_during_update = true;
     bool has_thumb = false;
     scoped_refptr<Layer> layer_tree_root = Layer::Create();
     scoped_refptr<FakePaintedScrollbarLayer> scrollbar_layer =
         FakePaintedScrollbarLayer::Create(paint_during_update,
                                           has_thumb,
                                           layer_tree_root->id());
 
     layer_tree_root->AddChild(scrollbar_layer);
 
@@ skipping 53 matching lines @@
   }
 
  protected:
   // On Android, Skia uses ABGR
   static SkColor argb_to_skia(SkColor c) {
       return (SkColorGetA(c) << SK_A32_SHIFT) |
              (SkColorGetR(c) << SK_R32_SHIFT) |
              (SkColorGetG(c) << SK_G32_SHIFT) |
              (SkColorGetB(c) << SK_B32_SHIFT);
   }
-
-  FakeLayerTreeHostClient fake_client_;
-  LayerTreeSettings layer_tree_settings_;
-  scoped_ptr<FakeLayerTreeHost> layer_tree_host_;
 };
 
 TEST_F(ScaledScrollbarLayerTestScaledRasterization, TestLostPrecisionInClip) {
   // Try rasterization at coordinates and scale that caused problematic
   // rounding and clipping errors.
   // Vertical Scrollbars.
   TestScale(gfx::Rect(1240, 0, 15, 1333), 2.7754839f);
   TestScale(gfx::Rect(1240, 0, 15, 677), 2.46677136f);
 
   // Horizontal Scrollbars.
   TestScale(gfx::Rect(0, 1240, 1333, 15), 2.7754839f);
   TestScale(gfx::Rect(0, 1240, 677, 15), 2.46677136f);
 }
 
 }  // namespace
 }  // namespace cc