Revert of cc: Remove use of PassAs() and constructor-casting with scoped_ptr. (patchset #6 id:120001 of https://codereview.chromium.org/609663003/)

Reason for revert:
scoped_ptr nullptr support needs to be reverted

Original issue's description:
> cc: Remove use of PassAs() and constructor-casting with scoped_ptr.
>
> Say you have class A and subclass B.
>
> Previously it was required to PassAs() a scoped_ptr<B> into a
> scoped_ptr<A>. This is no longer needed, so just use Pass(). For newly
> created scoped_ptrs, you can just use make_scoped_ptr always now.
>
> And when you want to return or assign an empty scoped_ptr(), you can
> now use nullptr directly.
>
> Also adds PRESUBMIT checks for:
> - return scoped<T>(foo). This should be return make_scoped_ptr(foo).
> - bar = scoped<T>(foo). This should be return bar = make_scoped_ptr(foo).
> - return scoped<T>(). This should be return nullptr.
> - bar = scoped<T>(). This should be return bar = nullptr.
>
> This also replaces p.reset() with p = nullptr; But it does not add a
> PRESUBMIT check for that because there are things other than scoped_ptr
> with a reset() function.
>
> R=enne@chromium.org
>
> Committed: https://crrev.com/7bb3dbede19d87f0338797756ffd738adc6bca08
> Cr-Commit-Position: refs/heads/master@{#297096}

TBR=enne@chromium.org,jamesr@chromium.org,vmpstr@chromium.org,danakj@chromium.org
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/608503005

Cr-Commit-Position: refs/heads/master@{#297106}

18 files changed, 170 insertions, 136 deletions

diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index 6b86eb6..78373c7 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -166,7 +166,7 @@ LayerTreeHost::~LayerTreeHost() {
 
   BreakSwapPromises(SwapPromise::COMMIT_FAILS);
 
-  overhang_ui_resource_ = nullptr;
+  overhang_ui_resource_.reset();
 
   if (root_layer_.get())
     root_layer_->SetLayerTreeHost(NULL);
@@ -366,7 +366,7 @@ void LayerTreeHost::FinishCommitOnImplThread(LayerTreeHostImpl* host_impl) {
         pending_page_scale_animation_->use_anchor,
         pending_page_scale_animation_->scale,
         pending_page_scale_animation_->duration);
-    pending_page_scale_animation_ = nullptr;
+    pending_page_scale_animation_.reset();
   }
 
   if (!ui_resource_request_queue_.empty()) {
diff --git a/cc/trees/layer_tree_host_common_unittest.cc b/cc/trees/layer_tree_host_common_unittest.cc
index 82e34fa..1efc110 100644
--- a/cc/trees/layer_tree_host_common_unittest.cc
+++ b/cc/trees/layer_tree_host_common_unittest.cc
@@ -7852,9 +7852,9 @@ TEST_F(LayerTreeHostCommonTest, MaximumAnimationScaleFactor) {
   AnimationScaleFactorTrackingLayerImpl* child_raw = child.get();
   AnimationScaleFactorTrackingLayerImpl* grand_child_raw = grand_child.get();
 
-  child->AddChild(grand_child.Pass());
-  parent->AddChild(child.Pass());
-  grand_parent->AddChild(parent.Pass());
+  child->AddChild(grand_child.PassAs<LayerImpl>());
+  parent->AddChild(child.PassAs<LayerImpl>());
+  grand_parent->AddChild(parent.PassAs<LayerImpl>());
 
   SetLayerPropertiesForTesting(grand_parent.get(),
                                identity_matrix,
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index 5771bbb..29e29c3 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -309,9 +309,9 @@ LayerTreeHostImpl::~LayerTreeHostImpl() {
   if (pending_tree_)
     pending_tree_->Shutdown();
   active_tree_->Shutdown();
-  recycle_tree_ = nullptr;
-  pending_tree_ = nullptr;
-  active_tree_ = nullptr;
+  recycle_tree_.reset();
+  pending_tree_.reset();
+  active_tree_.reset();
   DestroyTileManager();
 }
 
@@ -446,7 +446,7 @@ void LayerTreeHostImpl::StartPageScaleAnimation(
 
   // Easing constants experimentally determined.
   scoped_ptr<TimingFunction> timing_function =
-      CubicBezierTimingFunction::Create(.8, 0, .3, .9);
+      CubicBezierTimingFunction::Create(.8, 0, .3, .9).PassAs<TimingFunction>();
 
   page_scale_animation_ =
       PageScaleAnimation::Create(scroll_total,
@@ -506,7 +506,7 @@ bool LayerTreeHostImpl::HaveTouchEventHandlersAt(
 scoped_ptr<SwapPromiseMonitor>
 LayerTreeHostImpl::CreateLatencyInfoSwapPromiseMonitor(
     ui::LatencyInfo* latency) {
-  return make_scoped_ptr(
+  return scoped_ptr<SwapPromiseMonitor>(
       new LatencyInfoSwapPromiseMonitor(latency, NULL, this));
 }
 
@@ -1171,16 +1171,16 @@ void LayerTreeHostImpl::ResetTreesForTesting() {
   active_tree_ = LayerTreeImpl::create(this);
   if (pending_tree_)
     pending_tree_->DetachLayerTree();
-  pending_tree_ = nullptr;
+  pending_tree_.reset();
   if (recycle_tree_)
     recycle_tree_->DetachLayerTree();
-  recycle_tree_ = nullptr;
+  recycle_tree_.reset();
 }
 
 void LayerTreeHostImpl::ResetRecycleTreeForTesting() {
   if (recycle_tree_)
     recycle_tree_->DetachLayerTree();
-  recycle_tree_ = nullptr;
+  recycle_tree_.reset();
 }
 
 void LayerTreeHostImpl::EnforceManagedMemoryPolicy(
@@ -2041,10 +2041,10 @@ void LayerTreeHostImpl::CreateAndSetTileManager() {
 }
 
 void LayerTreeHostImpl::DestroyTileManager() {
-  tile_manager_ = nullptr;
-  resource_pool_ = nullptr;
-  staging_resource_pool_ = nullptr;
-  raster_worker_pool_ = nullptr;
+  tile_manager_.reset();
+  resource_pool_.reset();
+  staging_resource_pool_.reset();
+  raster_worker_pool_.reset();
 }
 
 bool LayerTreeHostImpl::UsePendingTreeForSync() const {
@@ -2077,10 +2077,10 @@ bool LayerTreeHostImpl::InitializeRenderer(
   ReleaseTreeResources();
 
   // Note: order is important here.
-  renderer_ = nullptr;
+  renderer_.reset();
   DestroyTileManager();
-  resource_provider_ = nullptr;
-  output_surface_ = nullptr;
+  resource_provider_.reset();
+  output_surface_.reset();
 
   if (!output_surface->BindToClient(this))
     return false;
@@ -2142,7 +2142,7 @@ void LayerTreeHostImpl::DeferredInitialize() {
   DCHECK(output_surface_->context_provider());
 
   ReleaseTreeResources();
-  renderer_ = nullptr;
+  renderer_.reset();
   DestroyTileManager();
 
   resource_provider_->InitializeGL();
@@ -2160,7 +2160,7 @@ void LayerTreeHostImpl::ReleaseGL() {
   DCHECK(output_surface_->context_provider());
 
   ReleaseTreeResources();
-  renderer_ = nullptr;
+  renderer_.reset();
   DestroyTileManager();
 
   resource_provider_->InitializeSoftware();
@@ -2428,7 +2428,7 @@ InputHandler::ScrollStatus LayerTreeHostImpl::ScrollAnimated(
       curve->SetInitialValue(current_offset);
 
       scoped_ptr<Animation> animation =
-          Animation::Create(curve.Pass(),
+          Animation::Create(curve.PassAs<AnimationCurve>(),
                             AnimationIdProvider::NextAnimationId(),
                             AnimationIdProvider::NextGroupId(),
                             Animation::ScrollOffset);
@@ -2992,7 +2992,7 @@ void LayerTreeHostImpl::AnimatePageScale(base::TimeTicks monotonic_time) {
   SetNeedsRedraw();
 
   if (page_scale_animation_->IsAnimationCompleteAtTime(monotonic_time)) {
-    page_scale_animation_ = nullptr;
+    page_scale_animation_.reset();
     client_->SetNeedsCommitOnImplThread();
     client_->RenewTreePriority();
   } else {
diff --git a/cc/trees/layer_tree_host_impl_unittest.cc b/cc/trees/layer_tree_host_impl_unittest.cc
index 2607431..85e6a91 100644
--- a/cc/trees/layer_tree_host_impl_unittest.cc
+++ b/cc/trees/layer_tree_host_impl_unittest.cc
@@ -379,7 +379,7 @@ class LayerTreeHostImplTest : public testing::Test,
 
  protected:
   virtual scoped_ptr<OutputSurface> CreateOutputSurface() {
-    return FakeOutputSurface::Create3d();
+    return FakeOutputSurface::Create3d().PassAs<OutputSurface>();
   }
 
   void DrawOneFrame() {
@@ -415,8 +415,9 @@ TEST_F(LayerTreeHostImplTest, NotifyIfCanDrawChanged) {
 }
 
 TEST_F(LayerTreeHostImplTest, CanDrawIncompleteFrames) {
-  CreateHostImpl(DefaultSettings(),
-                 FakeOutputSurface::CreateAlwaysDrawAndSwap3d());
+  scoped_ptr<FakeOutputSurface> output_surface(
+      FakeOutputSurface::CreateAlwaysDrawAndSwap3d());
+  CreateHostImpl(DefaultSettings(), output_surface.PassAs<OutputSurface>());
 
   bool always_draw = true;
   CheckNotifyCalledIfCanDrawChanged(always_draw);
@@ -526,9 +527,12 @@ TEST_F(LayerTreeHostImplTest, ScrollWithoutRenderer) {
       TestWebGraphicsContext3D::Create();
   context_owned->set_context_lost(true);
 
+  scoped_ptr<FakeOutputSurface> output_surface(FakeOutputSurface::Create3d(
+      context_owned.Pass()));
+
   // Initialization will fail.
-  EXPECT_FALSE(CreateHostImpl(
-      DefaultSettings(), FakeOutputSurface::Create3d(context_owned.Pass())));
+  EXPECT_FALSE(CreateHostImpl(DefaultSettings(),
+                              output_surface.PassAs<OutputSurface>()));
 
   SetupScrollAndContentsLayers(gfx::Size(100, 100));
 
@@ -1325,7 +1329,7 @@ class LayerTreeHostImplOverridePhysicalTime : public LayerTreeHostImpl {
   scroll->AddChild(contents.Pass());                                          \
   root->AddChild(scroll.Pass());                                              \
   scrollbar->SetScrollLayerAndClipLayerByIds(2, 1);                           \
-  root->AddChild(scrollbar.Pass());                                           \
+  root->AddChild(scrollbar.PassAs<LayerImpl>());                              \
                                                                               \
   host_impl_->active_tree()->SetRootLayer(root.Pass());                       \
   host_impl_->active_tree()->SetViewportLayersFromIds(                        \
@@ -1493,7 +1497,7 @@ void LayerTreeHostImplTest::SetupMouseMoveAtWithDeviceScale(
   scroll->AddChild(contents.Pass());
   root->AddChild(scroll.Pass());
   scrollbar->SetScrollLayerAndClipLayerByIds(2, 1);
-  root->AddChild(scrollbar.Pass());
+  root->AddChild(scrollbar.PassAs<LayerImpl>());
 
   host_impl_->active_tree()->SetRootLayer(root.Pass());
   host_impl_->active_tree()->SetViewportLayersFromIds(1, 2, Layer::INVALID_ID);
@@ -1607,7 +1611,7 @@ TEST_F(LayerTreeHostImplTest, CompositorFrameMetadata) {
 class DidDrawCheckLayer : public LayerImpl {
  public:
   static scoped_ptr<LayerImpl> Create(LayerTreeImpl* tree_impl, int id) {
-    return make_scoped_ptr(new DidDrawCheckLayer(tree_impl, id));
+    return scoped_ptr<LayerImpl>(new DidDrawCheckLayer(tree_impl, id));
   }
 
   virtual bool WillDraw(DrawMode draw_mode, ResourceProvider* provider)
@@ -1833,12 +1837,13 @@ class MissingTextureAnimatingLayer : public DidDrawCheckLayer {
                                       bool had_incomplete_tile,
                                       bool animating,
                                       ResourceProvider* resource_provider) {
-    return make_scoped_ptr(new MissingTextureAnimatingLayer(tree_impl,
-                                                            id,
-                                                            tile_missing,
-                                                            had_incomplete_tile,
-                                                            animating,
-                                                            resource_provider));
+    return scoped_ptr<LayerImpl>(
+        new MissingTextureAnimatingLayer(tree_impl,
+                                         id,
+                                         tile_missing,
+                                         had_incomplete_tile,
+                                         animating,
+                                         resource_provider));
   }
 
   virtual void AppendQuads(RenderPass* render_pass,
@@ -3635,8 +3640,9 @@ class BlendStateCheckLayer : public LayerImpl {
   static scoped_ptr<LayerImpl> Create(LayerTreeImpl* tree_impl,
                                       int id,
                                       ResourceProvider* resource_provider) {
-    return make_scoped_ptr(
-        new BlendStateCheckLayer(tree_impl, id, resource_provider));
+    return scoped_ptr<LayerImpl>(new BlendStateCheckLayer(tree_impl,
+                                                          id,
+                                                          resource_provider));
   }
 
   virtual void AppendQuads(RenderPass* render_pass,
@@ -3948,9 +3954,10 @@ class LayerTreeHostImplViewportCoveredTest : public LayerTreeHostImplTest {
 
   scoped_ptr<OutputSurface> CreateFakeOutputSurface(bool always_draw) {
     if (always_draw) {
-      return FakeOutputSurface::CreateAlwaysDrawAndSwap3d();
+      return FakeOutputSurface::CreateAlwaysDrawAndSwap3d()
+          .PassAs<OutputSurface>();
     }
-    return FakeOutputSurface::Create3d();
+    return FakeOutputSurface::Create3d().PassAs<OutputSurface>();
   }
 
   void SetupActiveTreeLayers() {
@@ -4230,7 +4237,7 @@ TEST_F(LayerTreeHostImplViewportCoveredTest, ActiveTreeShrinkViewportInvalid) {
 class FakeDrawableLayerImpl: public LayerImpl {
  public:
   static scoped_ptr<LayerImpl> Create(LayerTreeImpl* tree_impl, int id) {
-    return make_scoped_ptr(new FakeDrawableLayerImpl(tree_impl, id));
+    return scoped_ptr<LayerImpl>(new FakeDrawableLayerImpl(tree_impl, id));
   }
  protected:
   FakeDrawableLayerImpl(LayerTreeImpl* tree_impl, int id)
@@ -4400,7 +4407,7 @@ TEST_F(LayerTreeHostImplTest, RootLayerDoesntCreateExtraSurface) {
 class FakeLayerWithQuads : public LayerImpl {
  public:
   static scoped_ptr<LayerImpl> Create(LayerTreeImpl* tree_impl, int id) {
-    return make_scoped_ptr(new FakeLayerWithQuads(tree_impl, id));
+    return scoped_ptr<LayerImpl>(new FakeLayerWithQuads(tree_impl, id));
   }
 
   virtual void AppendQuads(RenderPass* render_pass,
@@ -4514,13 +4521,15 @@ class MockContextHarness {
 TEST_F(LayerTreeHostImplTest, NoPartialSwap) {
   scoped_ptr<MockContext> mock_context_owned(new MockContext);
   MockContext* mock_context = mock_context_owned.get();
+
+  scoped_ptr<OutputSurface> output_surface(FakeOutputSurface::Create3d(
+      mock_context_owned.PassAs<TestWebGraphicsContext3D>()));
   MockContextHarness harness(mock_context);
 
   // Run test case
   LayerTreeSettings settings = DefaultSettings();
   settings.partial_swap_enabled = false;
-  CreateHostImpl(settings,
-                 FakeOutputSurface::Create3d(mock_context_owned.Pass()));
+  CreateHostImpl(settings, output_surface.Pass());
   SetupRootLayerImpl(FakeLayerWithQuads::Create(host_impl_->active_tree(), 1));
 
   // Without partial swap, and no clipping, no scissor is set.
@@ -4551,11 +4560,13 @@ TEST_F(LayerTreeHostImplTest, NoPartialSwap) {
 TEST_F(LayerTreeHostImplTest, PartialSwap) {
   scoped_ptr<MockContext> context_owned(new MockContext);
   MockContext* mock_context = context_owned.get();
+  scoped_ptr<OutputSurface> output_surface(FakeOutputSurface::Create3d(
+      context_owned.PassAs<TestWebGraphicsContext3D>()));
   MockContextHarness harness(mock_context);
 
   LayerTreeSettings settings = DefaultSettings();
   settings.partial_swap_enabled = true;
-  CreateHostImpl(settings, FakeOutputSurface::Create3d(context_owned.Pass()));
+  CreateHostImpl(settings, output_surface.Pass());
   SetupRootLayerImpl(FakeLayerWithQuads::Create(host_impl_->active_tree(), 1));
 
   // The first frame is not a partially-swapped one.
@@ -4738,7 +4749,7 @@ TEST_F(LayerTreeHostImplTest, LayersFreeTextures) {
   video_layer->SetBounds(gfx::Size(10, 10));
   video_layer->SetContentBounds(gfx::Size(10, 10));
   video_layer->SetDrawsContent(true);
-  root_layer->AddChild(video_layer.Pass());
+  root_layer->AddChild(video_layer.PassAs<LayerImpl>());
 
   scoped_ptr<IOSurfaceLayerImpl> io_surface_layer =
       IOSurfaceLayerImpl::Create(host_impl_->active_tree(), 5);
@@ -4746,7 +4757,7 @@ TEST_F(LayerTreeHostImplTest, LayersFreeTextures) {
   io_surface_layer->SetContentBounds(gfx::Size(10, 10));
   io_surface_layer->SetDrawsContent(true);
   io_surface_layer->SetIOSurfaceProperties(1, gfx::Size(10, 10));
-  root_layer->AddChild(io_surface_layer.Pass());
+  root_layer->AddChild(io_surface_layer.PassAs<LayerImpl>());
 
   host_impl_->active_tree()->SetRootLayer(root_layer.Pass());
 
@@ -4781,11 +4792,13 @@ TEST_F(LayerTreeHostImplTest, HasTransparentBackground) {
       new MockDrawQuadsToFillScreenContext);
   MockDrawQuadsToFillScreenContext* mock_context = mock_context_owned.get();
 
+  scoped_ptr<OutputSurface> output_surface(FakeOutputSurface::Create3d(
+      mock_context_owned.PassAs<TestWebGraphicsContext3D>()));
+
   // Run test case
   LayerTreeSettings settings = DefaultSettings();
   settings.partial_swap_enabled = false;
-  CreateHostImpl(settings,
-                 FakeOutputSurface::Create3d(mock_context_owned.Pass()));
+  CreateHostImpl(settings, output_surface.Pass());
   SetupRootLayerImpl(LayerImpl::Create(host_impl_->active_tree(), 1));
   host_impl_->active_tree()->set_background_color(SK_ColorWHITE);
 
@@ -4854,7 +4867,7 @@ class LayerTreeHostImplTestWithDelegatingRenderer
     : public LayerTreeHostImplTest {
  protected:
   virtual scoped_ptr<OutputSurface> CreateOutputSurface() OVERRIDE {
-    return FakeOutputSurface::CreateDelegating3d();
+    return FakeOutputSurface::CreateDelegating3d().PassAs<OutputSurface>();
   }
 
   void DrawFrameAndTestDamage(const gfx::RectF& expected_damage) {
@@ -4909,9 +4922,9 @@ TEST_F(LayerTreeHostImplTestWithDelegatingRenderer, FrameIncludesDamageRect) {
   child->SetBounds(gfx::Size(1, 1));
   child->SetContentBounds(gfx::Size(1, 1));
   child->SetDrawsContent(true);
-  root->AddChild(child.Pass());
+  root->AddChild(child.PassAs<LayerImpl>());
 
-  host_impl_->active_tree()->SetRootLayer(root.Pass());
+  host_impl_->active_tree()->SetRootLayer(root.PassAs<LayerImpl>());
 
   // Draw a frame. In the first frame, the entire viewport should be damaged.
   gfx::Rect full_frame_damage(host_impl_->DrawViewportSize());
@@ -4981,7 +4994,7 @@ TEST_F(LayerTreeHostImplTest, MaskLayerWithScaling) {
   scoped_ptr<FakeMaskLayerImpl> scoped_mask_layer =
       FakeMaskLayerImpl::Create(host_impl_->active_tree(), 4);
   FakeMaskLayerImpl* mask_layer = scoped_mask_layer.get();
-  content_layer->SetMaskLayer(scoped_mask_layer.Pass());
+  content_layer->SetMaskLayer(scoped_mask_layer.PassAs<LayerImpl>());
 
   gfx::Size root_size(100, 100);
   root->SetBounds(root_size);
@@ -5110,7 +5123,7 @@ TEST_F(LayerTreeHostImplTest, MaskLayerWithDifferentBounds) {
   scoped_ptr<FakeMaskLayerImpl> scoped_mask_layer =
       FakeMaskLayerImpl::Create(host_impl_->active_tree(), 4);
   FakeMaskLayerImpl* mask_layer = scoped_mask_layer.get();
-  content_layer->SetMaskLayer(scoped_mask_layer.Pass());
+  content_layer->SetMaskLayer(scoped_mask_layer.PassAs<LayerImpl>());
 
   gfx::Size root_size(100, 100);
   root->SetBounds(root_size);
@@ -5261,7 +5274,7 @@ TEST_F(LayerTreeHostImplTest, ReflectionMaskLayerWithDifferentBounds) {
   scoped_ptr<FakeMaskLayerImpl> scoped_mask_layer =
       FakeMaskLayerImpl::Create(host_impl_->active_tree(), 4);
   FakeMaskLayerImpl* mask_layer = scoped_mask_layer.get();
-  replica_layer->SetMaskLayer(scoped_mask_layer.Pass());
+  replica_layer->SetMaskLayer(scoped_mask_layer.PassAs<LayerImpl>());
 
   gfx::Size root_size(100, 100);
   root->SetBounds(root_size);
@@ -5413,7 +5426,7 @@ TEST_F(LayerTreeHostImplTest, ReflectionMaskLayerForSurfaceWithUnclippedChild) {
   scoped_ptr<FakeMaskLayerImpl> scoped_mask_layer =
       FakeMaskLayerImpl::Create(host_impl_->active_tree(), 5);
   FakeMaskLayerImpl* mask_layer = scoped_mask_layer.get();
-  replica_layer->SetMaskLayer(scoped_mask_layer.Pass());
+  replica_layer->SetMaskLayer(scoped_mask_layer.PassAs<LayerImpl>());
 
   gfx::Size root_size(100, 100);
   root->SetBounds(root_size);
@@ -5533,7 +5546,7 @@ TEST_F(LayerTreeHostImplTest, MaskLayerForSurfaceWithClippedLayer) {
   scoped_ptr<FakeMaskLayerImpl> scoped_mask_layer =
       FakeMaskLayerImpl::Create(host_impl_->active_tree(), 6);
   FakeMaskLayerImpl* mask_layer = scoped_mask_layer.get();
-  content_layer->SetMaskLayer(scoped_mask_layer.Pass());
+  content_layer->SetMaskLayer(scoped_mask_layer.PassAs<LayerImpl>());
 
   gfx::Size root_size(100, 100);
   root->SetBounds(root_size);
@@ -5634,7 +5647,7 @@ TEST_F(LayerTreeHostImplTest, FarAwayQuadsDontNeedAA) {
   scoped_ptr<FakePictureLayerImpl> scoped_content_layer =
       FakePictureLayerImpl::CreateWithPile(host_impl_->pending_tree(), 3, pile);
   LayerImpl* content_layer = scoped_content_layer.get();
-  scrolling_layer->AddChild(scoped_content_layer.Pass());
+  scrolling_layer->AddChild(scoped_content_layer.PassAs<LayerImpl>());
   content_layer->SetBounds(content_layer_bounds);
   content_layer->SetDrawsContent(true);
 
@@ -5782,8 +5795,8 @@ TEST_F(LayerTreeHostImplTest,
   video_layer->SetBounds(gfx::Size(10, 10));
   video_layer->SetContentBounds(gfx::Size(10, 10));
   video_layer->SetDrawsContent(true);
-  root_layer->AddChild(video_layer.Pass());
-  SetupRootLayerImpl(root_layer.Pass());
+  root_layer->AddChild(video_layer.PassAs<LayerImpl>());
+  SetupRootLayerImpl(root_layer.PassAs<LayerImpl>());
 
   LayerTreeHostImpl::FrameData frame;
   EXPECT_EQ(DRAW_SUCCESS, host_impl_->PrepareToDraw(&frame));
@@ -5808,11 +5821,12 @@ class LayerTreeHostImplTestDeferredInitialize : public LayerTreeHostImplTest {
             delegated_rendering));
     output_surface_ = output_surface.get();
 
-    EXPECT_TRUE(CreateHostImpl(DefaultSettings(), output_surface.Pass()));
+    EXPECT_TRUE(CreateHostImpl(DefaultSettings(),
+                               output_surface.PassAs<OutputSurface>()));
 
     scoped_ptr<SolidColorLayerImpl> root_layer =
         SolidColorLayerImpl::Create(host_impl_->active_tree(), 1);
-    SetupRootLayerImpl(root_layer.Pass());
+    SetupRootLayerImpl(root_layer.PassAs<LayerImpl>());
 
     onscreen_context_provider_ = TestContextProvider::Create();
   }
@@ -6010,7 +6024,7 @@ TEST_F(LayerTreeHostImplTest, UIResourceManagement) {
       TestWebGraphicsContext3D::Create();
   TestWebGraphicsContext3D* context3d = context.get();
   scoped_ptr<FakeOutputSurface> output_surface = FakeOutputSurface::Create3d();
-  CreateHostImpl(DefaultSettings(), output_surface.Pass());
+  CreateHostImpl(DefaultSettings(), output_surface.PassAs<OutputSurface>());
 
   EXPECT_EQ(0u, context3d->NumTextures());
 
@@ -6054,7 +6068,8 @@ TEST_F(LayerTreeHostImplTest, CreateETC1UIResource) {
   scoped_ptr<TestWebGraphicsContext3D> context =
       TestWebGraphicsContext3D::Create();
   TestWebGraphicsContext3D* context3d = context.get();
-  CreateHostImpl(DefaultSettings(), FakeOutputSurface::Create3d());
+  scoped_ptr<FakeOutputSurface> output_surface = FakeOutputSurface::Create3d();
+  CreateHostImpl(DefaultSettings(), output_surface.PassAs<OutputSurface>());
 
   EXPECT_EQ(0u, context3d->NumTextures());
 
@@ -6083,8 +6098,9 @@ TEST_F(LayerTreeHostImplTest, ShutdownReleasesContext) {
   scoped_refptr<TestContextProvider> context_provider =
       TestContextProvider::Create();
 
-  CreateHostImpl(DefaultSettings(),
-                 FakeOutputSurface::Create3d(context_provider));
+  CreateHostImpl(
+      DefaultSettings(),
+      FakeOutputSurface::Create3d(context_provider).PassAs<OutputSurface>());
 
   SetupRootLayerImpl(LayerImpl::Create(host_impl_->active_tree(), 1));
 
@@ -6104,7 +6120,7 @@ TEST_F(LayerTreeHostImplTest, ShutdownReleasesContext) {
   EXPECT_FALSE(context_provider->HasOneRef());
   EXPECT_EQ(1u, context_provider->TestContext3d()->NumTextures());
 
-  host_impl_ = nullptr;
+  host_impl_.reset();
 
   // The CopyOutputResult's callback was cancelled, the CopyOutputResult
   // released, and the texture deleted.
@@ -6436,7 +6452,7 @@ TEST_F(LayerTreeHostImplTest, LatencyInfoPassedToCompositorFrameMetadata) {
   root->SetContentBounds(gfx::Size(10, 10));
   root->SetDrawsContent(true);
 
-  host_impl_->active_tree()->SetRootLayer(root.Pass());
+  host_impl_->active_tree()->SetRootLayer(root.PassAs<LayerImpl>());
 
   FakeOutputSurface* fake_output_surface =
       static_cast<FakeOutputSurface*>(host_impl_->output_surface());
@@ -6476,7 +6492,7 @@ TEST_F(LayerTreeHostImplTest, SelectionBoundsPassedToCompositorFrameMetadata) {
   root->SetContentBounds(gfx::Size(10, 10));
   root->SetDrawsContent(true);
 
-  host_impl_->active_tree()->SetRootLayer(root.Pass());
+  host_impl_->active_tree()->SetRootLayer(root.PassAs<LayerImpl>());
 
   // Ensure the default frame selection bounds are empty.
   FakeOutputSurface* fake_output_surface =
@@ -7110,7 +7126,7 @@ TEST_F(LayerTreeHostImplTest, DidBecomeActive) {
       FakePictureLayerImpl::Create(pending_tree, 10);
   pending_layer->DoPostCommitInitializationIfNeeded();
   FakePictureLayerImpl* raw_pending_layer = pending_layer.get();
-  pending_tree->SetRootLayer(pending_layer.Pass());
+  pending_tree->SetRootLayer(pending_layer.PassAs<LayerImpl>());
   ASSERT_EQ(raw_pending_layer, pending_tree->root_layer());
 
   EXPECT_EQ(0u, raw_pending_layer->did_become_active_call_count());
@@ -7121,7 +7137,7 @@ TEST_F(LayerTreeHostImplTest, DidBecomeActive) {
       FakePictureLayerImpl::Create(pending_tree, 11);
   mask_layer->DoPostCommitInitializationIfNeeded();
   FakePictureLayerImpl* raw_mask_layer = mask_layer.get();
-  raw_pending_layer->SetMaskLayer(mask_layer.Pass());
+  raw_pending_layer->SetMaskLayer(mask_layer.PassAs<LayerImpl>());
   ASSERT_EQ(raw_mask_layer, raw_pending_layer->mask_layer());
 
   EXPECT_EQ(1u, raw_pending_layer->did_become_active_call_count());
@@ -7136,8 +7152,8 @@ TEST_F(LayerTreeHostImplTest, DidBecomeActive) {
       FakePictureLayerImpl::Create(pending_tree, 13);
   replica_mask_layer->DoPostCommitInitializationIfNeeded();
   FakePictureLayerImpl* raw_replica_mask_layer = replica_mask_layer.get();
-  replica_layer->SetMaskLayer(replica_mask_layer.Pass());
-  raw_pending_layer->SetReplicaLayer(replica_layer.Pass());
+  replica_layer->SetMaskLayer(replica_mask_layer.PassAs<LayerImpl>());
+  raw_pending_layer->SetReplicaLayer(replica_layer.PassAs<LayerImpl>());
   ASSERT_EQ(raw_replica_mask_layer,
             raw_pending_layer->replica_layer()->mask_layer());
 
diff --git a/cc/trees/layer_tree_host_unittest.cc b/cc/trees/layer_tree_host_unittest.cc
index 7f9eb3b..876d8ae 100644
--- a/cc/trees/layer_tree_host_unittest.cc
+++ b/cc/trees/layer_tree_host_unittest.cc
@@ -1664,7 +1664,8 @@ bool EvictionTestLayer::Update(ResourceUpdateQueue* queue,
 
 scoped_ptr<LayerImpl> EvictionTestLayer::CreateLayerImpl(
     LayerTreeImpl* tree_impl) {
-  return EvictionTestLayerImpl::Create(tree_impl, layer_id_);
+  return EvictionTestLayerImpl::Create(tree_impl, layer_id_)
+      .PassAs<LayerImpl>();
 }
 
 void EvictionTestLayer::PushPropertiesTo(LayerImpl* layer_impl) {
@@ -1902,7 +1903,7 @@ class LayerTreeHostWithProxy : public LayerTreeHost {
       : LayerTreeHost(client, NULL, settings) {
     proxy->SetLayerTreeHost(this);
     client->SetLayerTreeHost(this);
-    InitializeForTesting(proxy.Pass());
+    InitializeForTesting(proxy.PassAs<Proxy>());
   }
 };
 
@@ -2475,10 +2476,13 @@ class LayerTreeHostTestIOSurfaceDrawing : public LayerTreeHostTest {
         new MockIOSurfaceWebGraphicsContext3D);
     mock_context_ = mock_context_owned.get();
 
-    if (delegating_renderer())
-      return FakeOutputSurface::CreateDelegating3d(mock_context_owned.Pass());
-    else
-      return FakeOutputSurface::Create3d(mock_context_owned.Pass());
+    if (delegating_renderer()) {
+      return FakeOutputSurface::CreateDelegating3d(
+          mock_context_owned.PassAs<TestWebGraphicsContext3D>());
+    } else {
+      return FakeOutputSurface::Create3d(
+          mock_context_owned.PassAs<TestWebGraphicsContext3D>());
+    }
   }
 
   virtual void SetupTree() OVERRIDE {
@@ -2864,7 +2868,7 @@ class LayerTreeHostTestUIResource : public LayerTreeHostTest {
   // Must clear all resources before exiting.
   void ClearResources() {
     for (int i = 0; i < num_ui_resources_; i++)
-      ui_resources_[i] = nullptr;
+      ui_resources_[i].reset();
   }
 
   void CreateResource() {
@@ -2897,7 +2901,8 @@ class PushPropertiesCountingLayerImpl : public LayerImpl {
 
   virtual scoped_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl)
       OVERRIDE {
-    return PushPropertiesCountingLayerImpl::Create(tree_impl, id());
+    return PushPropertiesCountingLayerImpl::Create(tree_impl, id()).
+        PassAs<LayerImpl>();
   }
 
   size_t push_properties_count() const { return push_properties_count_; }
@@ -2928,7 +2933,8 @@ class PushPropertiesCountingLayer : public Layer {
 
   virtual scoped_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl)
       OVERRIDE {
-    return PushPropertiesCountingLayerImpl::Create(tree_impl, id());
+    return PushPropertiesCountingLayerImpl::Create(tree_impl, id()).
+        PassAs<LayerImpl>();
   }
 
   void SetDrawsContent(bool draws_content) { SetIsDrawable(draws_content); }
@@ -4728,7 +4734,7 @@ class LayerTreeHostTestHighResRequiredAfterEvictingUIResources
         PostSetNeedsCommitToMainThread();
         break;
       case 2:
-        ui_resource_ = nullptr;
+        ui_resource_.reset();
         EndTest();
         break;
     }
diff --git a/cc/trees/layer_tree_host_unittest_animation.cc b/cc/trees/layer_tree_host_unittest_animation.cc
index d7668c1..37e19ad 100644
--- a/cc/trees/layer_tree_host_unittest_animation.cc
+++ b/cc/trees/layer_tree_host_unittest_animation.cc
@@ -1044,8 +1044,8 @@ class LayerTreeHostAnimationTestScrollOffsetChangesArePropagated
             ScrollOffsetAnimationCurve::Create(
                 gfx::Vector2dF(500.f, 550.f),
                 EaseInOutTimingFunction::Create()));
-        scoped_ptr<Animation> animation(
-            Animation::Create(curve.Pass(), 1, 0, Animation::ScrollOffset));
+        scoped_ptr<Animation> animation(Animation::Create(
+            curve.PassAs<AnimationCurve>(), 1, 0, Animation::ScrollOffset));
         animation->set_needs_synchronized_start_time(true);
         bool animation_added = scroll_layer_->AddAnimation(animation.Pass());
         bool impl_scrolling_supported =
diff --git a/cc/trees/layer_tree_host_unittest_context.cc b/cc/trees/layer_tree_host_unittest_context.cc
index 07e12a2..75c2842 100644
--- a/cc/trees/layer_tree_host_unittest_context.cc
+++ b/cc/trees/layer_tree_host_unittest_context.cc
@@ -86,7 +86,7 @@ class LayerTreeHostContextTest : public LayerTreeTest {
     if (times_to_fail_create_) {
       --times_to_fail_create_;
       ExpectCreateToFail();
-      return nullptr;
+      return scoped_ptr<FakeOutputSurface>();
     }
 
     scoped_ptr<TestWebGraphicsContext3D> context3d = CreateContext3d();
@@ -363,7 +363,7 @@ class LayerTreeHostClientNotReadyDoesNotCreateOutputSurface
   virtual scoped_ptr<OutputSurface> CreateOutputSurface(bool fallback)
       OVERRIDE {
     EXPECT_TRUE(false);
-    return nullptr;
+    return scoped_ptr<OutputSurface>();
   }
 
   virtual void DidInitializeOutputSurface() OVERRIDE { EXPECT_TRUE(false); }
@@ -878,8 +878,8 @@ class LayerTreeHostContextTestDontUseLostResources
     pass->AppendOneOfEveryQuadType(child_resource_provider_.get(),
                                    RenderPassId(2, 1));
 
-    frame_data->render_pass_list.push_back(pass_for_quad.Pass());
-    frame_data->render_pass_list.push_back(pass.Pass());
+    frame_data->render_pass_list.push_back(pass_for_quad.PassAs<RenderPass>());
+    frame_data->render_pass_list.push_back(pass.PassAs<RenderPass>());
 
     delegated_resource_collection_ = new DelegatedFrameResourceCollection;
     delegated_frame_provider_ = new DelegatedFrameProvider(
@@ -1256,7 +1256,7 @@ class UIResourceLostAfterCommit : public UIResourceLostTestSimple {
         break;
       case 4:
         // Release resource before ending the test.
-        ui_resource_ = nullptr;
+        ui_resource_.reset();
         EndTest();
         break;
       case 5:
@@ -1316,7 +1316,7 @@ class UIResourceLostBeforeCommit : public UIResourceLostTestSimple {
         // Currently one resource has been created.
         test_id0_ = ui_resource_->id();
         // Delete this resource.
-        ui_resource_ = nullptr;
+        ui_resource_.reset();
         // Create another resource.
         ui_resource_ = FakeScopedUIResource::Create(layer_tree_host());
         test_id1_ = ui_resource_->id();
@@ -1327,7 +1327,7 @@ class UIResourceLostBeforeCommit : public UIResourceLostTestSimple {
         break;
       case 3:
         // Clear the manager of resources.
-        ui_resource_ = nullptr;
+        ui_resource_.reset();
         PostSetNeedsCommitToMainThread();
         break;
       case 4:
@@ -1337,7 +1337,7 @@ class UIResourceLostBeforeCommit : public UIResourceLostTestSimple {
         // Sanity check the UIResourceId should not be 0.
         EXPECT_NE(0, test_id0_);
         // Usually ScopedUIResource are deleted from the manager in their
-        // destructor (so usually ui_resource_ = nullptr).  But here we need
+        // destructor (so usually ui_resource_.reset()).  But here we need
         // ui_resource_ for the next step, so call DeleteUIResource directly.
         layer_tree_host()->DeleteUIResource(test_id0_);
         // Delete the resouce and then lose the context.
@@ -1345,7 +1345,7 @@ class UIResourceLostBeforeCommit : public UIResourceLostTestSimple {
         break;
       case 5:
         // Release resource before ending the test.
-        ui_resource_ = nullptr;
+        ui_resource_.reset();
         EndTest();
         break;
       case 6:
@@ -1409,12 +1409,12 @@ class UIResourceLostBeforeActivateTree : public UIResourceLostTest {
         break;
       case 3:
         test_id_ = ui_resource_->id();
-        ui_resource_ = nullptr;
+        ui_resource_.reset();
         PostSetNeedsCommitToMainThread();
         break;
       case 5:
         // Release resource before ending the test.
-        ui_resource_ = nullptr;
+        ui_resource_.reset();
         EndTest();
         break;
       case 6:
@@ -1505,7 +1505,7 @@ class UIResourceLostEviction : public UIResourceLostTestSimple {
         break;
       case 3:
         // Release resource before ending the test.
-        ui_resource_ = nullptr;
+        ui_resource_.reset();
         EndTest();
         break;
       case 4:
diff --git a/cc/trees/layer_tree_host_unittest_copyrequest.cc b/cc/trees/layer_tree_host_unittest_copyrequest.cc
index 6af1756..89a267a 100644
--- a/cc/trees/layer_tree_host_unittest_copyrequest.cc
+++ b/cc/trees/layer_tree_host_unittest_copyrequest.cc
@@ -592,7 +592,7 @@ class LayerTreeHostCopyRequestTestLostOutputSurface
         // Now destroy the CopyOutputResult, releasing the texture inside back
         // to the compositor.
         EXPECT_TRUE(result_);
-        result_ = nullptr;
+        result_.reset();
 
         // Check that it is released.
         ImplThreadTaskRunner()->PostTask(
diff --git a/cc/trees/layer_tree_host_unittest_no_message_loop.cc b/cc/trees/layer_tree_host_unittest_no_message_loop.cc
index 9e38f1c..862f34bb 100644
--- a/cc/trees/layer_tree_host_unittest_no_message_loop.cc
+++ b/cc/trees/layer_tree_host_unittest_no_message_loop.cc
@@ -113,8 +113,8 @@ class LayerTreeHostNoMessageLoopTest
 
   void TearDownLayerTreeHost() {
     // Explicit teardown to make failures easier to debug.
-    layer_tree_host_ = nullptr;
-    root_layer_ = nullptr;
+    layer_tree_host_.reset();
+    root_layer_ = NULL;
   }
 
   // All protected member variables are accessed only on |no_loop_thread_|.
diff --git a/cc/trees/layer_tree_host_unittest_scroll.cc b/cc/trees/layer_tree_host_unittest_scroll.cc
index 9f2786c..d2db83a 100644
--- a/cc/trees/layer_tree_host_unittest_scroll.cc
+++ b/cc/trees/layer_tree_host_unittest_scroll.cc
@@ -1121,7 +1121,7 @@ TEST(LayerTreeHostFlingTest, DidStopFlingingThread) {
                             base::Unretained(&input_handler_client)));
 
   layer_tree_host->DidStopFlinging();
-  layer_tree_host = nullptr;
+  layer_tree_host.reset();
   impl_thread.Stop();
   EXPECT_TRUE(received_stop_flinging);
 }
diff --git a/cc/trees/layer_tree_impl.cc b/cc/trees/layer_tree_impl.cc
index ea9c1d01..6e44bfc 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -108,9 +108,7 @@ LayerTreeImpl::~LayerTreeImpl() {
   DCHECK(layers_with_copy_output_request_.empty());
 }
 
-void LayerTreeImpl::Shutdown() {
-  root_layer_ = nullptr;
-}
+void LayerTreeImpl::Shutdown() { root_layer_.reset(); }
 
 void LayerTreeImpl::ReleaseResources() {
   if (root_layer_)
@@ -122,8 +120,8 @@ void LayerTreeImpl::SetRootLayer(scoped_ptr<LayerImpl> layer) {
     inner_viewport_scroll_layer_->SetScrollOffsetDelegate(NULL);
   if (outer_viewport_scroll_layer_)
     outer_viewport_scroll_layer_->SetScrollOffsetDelegate(NULL);
-  inner_viewport_scroll_delegate_proxy_ = nullptr;
-  outer_viewport_scroll_delegate_proxy_ = nullptr;
+  inner_viewport_scroll_delegate_proxy_.reset();
+  outer_viewport_scroll_delegate_proxy_.reset();
 
   root_layer_ = layer.Pass();
   currently_scrolling_layer_ = NULL;
@@ -183,8 +181,8 @@ scoped_ptr<LayerImpl> LayerTreeImpl::DetachLayerTree() {
     inner_viewport_scroll_layer_->SetScrollOffsetDelegate(NULL);
   if (outer_viewport_scroll_layer_)
     outer_viewport_scroll_layer_->SetScrollOffsetDelegate(NULL);
-  inner_viewport_scroll_delegate_proxy_ = nullptr;
-  outer_viewport_scroll_delegate_proxy_ = nullptr;
+  inner_viewport_scroll_delegate_proxy_.reset();
+  outer_viewport_scroll_delegate_proxy_.reset();
   inner_viewport_scroll_layer_ = NULL;
   outer_viewport_scroll_layer_ = NULL;
   page_scale_layer_ = NULL;
@@ -785,17 +783,19 @@ LayerTreeImpl::CreateScrollbarAnimationController(LayerImpl* scrolling_layer) {
   switch (settings().scrollbar_animator) {
     case LayerTreeSettings::LinearFade: {
       return ScrollbarAnimationControllerLinearFade::Create(
-          scrolling_layer, layer_tree_host_impl_, delay, duration);
+                 scrolling_layer, layer_tree_host_impl_, delay, duration)
+          .PassAs<ScrollbarAnimationController>();
     }
     case LayerTreeSettings::Thinning: {
       return ScrollbarAnimationControllerThinning::Create(
-          scrolling_layer, layer_tree_host_impl_, delay, duration);
+                 scrolling_layer, layer_tree_host_impl_, delay, duration)
+          .PassAs<ScrollbarAnimationController>();
     }
     case LayerTreeSettings::NoAnimator:
       NOTREACHED();
       break;
   }
-  return nullptr;
+  return scoped_ptr<ScrollbarAnimationController>();
 }
 
 void LayerTreeImpl::DidAnimateScrollOffset() {
@@ -881,8 +881,8 @@ void LayerTreeImpl::SetRootLayerScrollOffsetDelegate(
       InnerViewportScrollLayer()->SetScrollOffsetDelegate(NULL);
     if (OuterViewportScrollLayer())
       OuterViewportScrollLayer()->SetScrollOffsetDelegate(NULL);
-    inner_viewport_scroll_delegate_proxy_ = nullptr;
-    outer_viewport_scroll_delegate_proxy_ = nullptr;
+    inner_viewport_scroll_delegate_proxy_.reset();
+    outer_viewport_scroll_delegate_proxy_.reset();
   }
 
   root_layer_scroll_offset_delegate_ = root_layer_scroll_offset_delegate;
diff --git a/cc/trees/layer_tree_impl_unittest.cc b/cc/trees/layer_tree_impl_unittest.cc
index 7fc1645..a0dd11a 100644
--- a/cc/trees/layer_tree_impl_unittest.cc
+++ b/cc/trees/layer_tree_impl_unittest.cc
@@ -25,7 +25,8 @@ class LayerTreeImplTest : public LayerTreeHostCommonTest {
     settings.layer_transforms_should_scale_layer_contents = true;
     host_impl_.reset(
         new FakeLayerTreeHostImpl(settings, &proxy_, &shared_bitmap_manager_));
-    EXPECT_TRUE(host_impl_->InitializeRenderer(FakeOutputSurface::Create3d()));
+    EXPECT_TRUE(host_impl_->InitializeRenderer(
+        FakeOutputSurface::Create3d().PassAs<OutputSurface>()));
   }
 
   FakeLayerTreeHostImpl& host_impl() { return *host_impl_; }
@@ -123,7 +124,7 @@ TEST_F(LayerTreeImplTest, HitTestingForSingleLayerAndHud) {
   hud->SetDrawsContent(true);
 
   host_impl().active_tree()->set_hud_layer(hud.get());
-  root->AddChild(hud.Pass());
+  root->AddChild(hud.PassAs<LayerImpl>());
 
   host_impl().SetViewportSize(hud_bounds);
   host_impl().active_tree()->SetRootLayer(root.Pass());
diff --git a/cc/trees/occlusion_tracker_perftest.cc b/cc/trees/occlusion_tracker_perftest.cc
index 37cd8a6..14a9ffd 100644
--- a/cc/trees/occlusion_tracker_perftest.cc
+++ b/cc/trees/occlusion_tracker_perftest.cc
@@ -38,7 +38,8 @@ class OcclusionTrackerPerfTest : public testing::Test {
     shared_bitmap_manager_.reset(new TestSharedBitmapManager());
     host_impl_ = LayerTreeHostImpl::Create(
         settings, &client_, &proxy_, &stats_, shared_bitmap_manager_.get(), 1);
-    host_impl_->InitializeRenderer(FakeOutputSurface::Create3d());
+    host_impl_->InitializeRenderer(
+        FakeOutputSurface::Create3d().PassAs<OutputSurface>());
 
     scoped_ptr<LayerImpl> root_layer = LayerImpl::Create(active_tree(), 1);
     active_tree()->SetRootLayer(root_layer.Pass());
@@ -85,7 +86,7 @@ TEST_F(OcclusionTrackerPerfTest, UnoccludedContentRect_FullyOccluded) {
   opaque_layer->SetDrawsContent(true);
   opaque_layer->SetBounds(viewport_rect.size());
   opaque_layer->SetContentBounds(viewport_rect.size());
-  active_tree()->root_layer()->AddChild(opaque_layer.Pass());
+  active_tree()->root_layer()->AddChild(opaque_layer.PassAs<LayerImpl>());
 
   active_tree()->UpdateDrawProperties();
   const LayerImplList& rsll = active_tree()->RenderSurfaceLayerList();
@@ -155,7 +156,7 @@ TEST_F(OcclusionTrackerPerfTest, UnoccludedContentRect_10OpaqueLayers) {
     opaque_layer->SetContentBounds(
         gfx::Size(viewport_rect.width() / 2, viewport_rect.height() / 2));
     opaque_layer->SetPosition(gfx::Point(i, i));
-    active_tree()->root_layer()->AddChild(opaque_layer.Pass());
+    active_tree()->root_layer()->AddChild(opaque_layer.PassAs<LayerImpl>());
   }
 
   active_tree()->UpdateDrawProperties();
diff --git a/cc/trees/occlusion_tracker_unittest.cc b/cc/trees/occlusion_tracker_unittest.cc
index 3c6c440..b35e437 100644
--- a/cc/trees/occlusion_tracker_unittest.cc
+++ b/cc/trees/occlusion_tracker_unittest.cc
@@ -121,8 +121,13 @@ struct OcclusionTrackerTestMainThreadTypes {
     return make_scoped_refptr(new ContentLayerType());
   }
 
-  template <typename T>
-  static LayerPtrType PassLayerPtr(T* layer) {
+  static LayerPtrType PassLayerPtr(ContentLayerPtrType* layer) {
+    LayerPtrType ref(*layer);
+    *layer = NULL;
+    return ref;
+  }
+
+  static LayerPtrType PassLayerPtr(LayerPtrType* layer) {
     LayerPtrType ref(*layer);
     *layer = NULL;
     return ref;
@@ -151,11 +156,14 @@ struct OcclusionTrackerTestImplThreadTypes {
   }
   static int next_layer_impl_id;
 
-  template <typename T>
-  static LayerPtrType PassLayerPtr(T* layer) {
+  static LayerPtrType PassLayerPtr(LayerPtrType* layer) {
     return layer->Pass();
   }
 
+  static LayerPtrType PassLayerPtr(ContentLayerPtrType* layer) {
+    return layer->PassAs<LayerType>();
+  }
+
   static void DestroyLayer(LayerPtrType* layer) { layer->reset(); }
 
   static void RecursiveUpdateNumChildren(LayerType* layer) {
@@ -278,7 +286,7 @@ template <typename Types> class OcclusionTrackerTest : public testing::Test {
 
   void DestroyLayers() {
     Types::DestroyLayer(&root_);
-    render_surface_layer_list_ = nullptr;
+    render_surface_layer_list_.reset();
     render_surface_layer_list_impl_.clear();
     replica_layers_.clear();
     mask_layers_.clear();
diff --git a/cc/trees/single_thread_proxy.cc b/cc/trees/single_thread_proxy.cc
index b3712b6..97b06bc 100644
--- a/cc/trees/single_thread_proxy.cc
+++ b/cc/trees/single_thread_proxy.cc
@@ -26,7 +26,8 @@ scoped_ptr<Proxy> SingleThreadProxy::Create(
     LayerTreeHostSingleThreadClient* client,
     scoped_refptr<base::SingleThreadTaskRunner> main_task_runner) {
   return make_scoped_ptr(
-      new SingleThreadProxy(layer_tree_host, client, main_task_runner));
+             new SingleThreadProxy(layer_tree_host, client, main_task_runner))
+      .PassAs<Proxy>();
 }
 
 SingleThreadProxy::SingleThreadProxy(
@@ -313,8 +314,8 @@ void SingleThreadProxy::Stop() {
         blocking_main_thread_task_runner());
     layer_tree_host_->DeleteContentsTexturesOnImplThread(
         layer_tree_host_impl_->resource_provider());
-    scheduler_on_impl_thread_ = nullptr;
-    layer_tree_host_impl_ = nullptr;
+    scheduler_on_impl_thread_.reset();
+    layer_tree_host_impl_.reset();
   }
   layer_tree_host_ = NULL;
 }
diff --git a/cc/trees/thread_proxy.cc b/cc/trees/thread_proxy.cc
index 151cb3c..dddf112 100644
--- a/cc/trees/thread_proxy.cc
+++ b/cc/trees/thread_proxy.cc
@@ -49,8 +49,9 @@ scoped_ptr<Proxy> ThreadProxy::Create(
     LayerTreeHost* layer_tree_host,
     scoped_refptr<base::SingleThreadTaskRunner> main_task_runner,
     scoped_refptr<base::SingleThreadTaskRunner> impl_task_runner) {
-  return make_scoped_ptr(
-      new ThreadProxy(layer_tree_host, main_task_runner, impl_task_runner));
+  return make_scoped_ptr(new ThreadProxy(layer_tree_host,
+                                         main_task_runner,
+                                         impl_task_runner)).PassAs<Proxy>();
 }
 
 ThreadProxy::ThreadProxy(
@@ -962,7 +963,7 @@ void ThreadProxy::ScheduledActionCommit() {
 
   // Complete all remaining texture updates.
   impl().current_resource_update_controller->Finalize();
-  impl().current_resource_update_controller = nullptr;
+  impl().current_resource_update_controller.reset();
 
   if (impl().animations_frozen_until_next_draw) {
     impl().animation_time = std::max(
@@ -1248,10 +1249,10 @@ void ThreadProxy::LayerTreeHostClosedOnImplThread(CompletionEvent* completion) {
   DCHECK(IsMainThreadBlocked());
   layer_tree_host()->DeleteContentsTexturesOnImplThread(
       impl().layer_tree_host_impl->resource_provider());
-  impl().current_resource_update_controller = nullptr;
+  impl().current_resource_update_controller.reset();
   impl().layer_tree_host_impl->SetNeedsBeginFrame(false);
-  impl().scheduler = nullptr;
-  impl().layer_tree_host_impl = nullptr;
+  impl().scheduler.reset();
+  impl().layer_tree_host_impl.reset();
   impl().weak_factory.InvalidateWeakPtrs();
   // We need to explicitly cancel the notifier, since it isn't using weak ptrs.
   // TODO(vmpstr): We should see if we can make it use weak ptrs and still keep
diff --git a/cc/trees/tree_synchronizer.cc b/cc/trees/tree_synchronizer.cc
index d17f017..1faf0e0 100644
--- a/cc/trees/tree_synchronizer.cc
+++ b/cc/trees/tree_synchronizer.cc
@@ -105,7 +105,7 @@ scoped_ptr<LayerImpl> SynchronizeTreesRecursiveInternal(
     LayerType* layer,
     LayerTreeImpl* tree_impl) {
   if (!layer)
-    return nullptr;
+    return scoped_ptr<LayerImpl>();
 
   scoped_ptr<LayerImpl> layer_impl =
       ReuseOrCreateLayerImpl(new_layers, old_layers, layer, tree_impl);
diff --git a/cc/trees/tree_synchronizer_unittest.cc b/cc/trees/tree_synchronizer_unittest.cc
index 007c857..b0e2114 100644
--- a/cc/trees/tree_synchronizer_unittest.cc
+++ b/cc/trees/tree_synchronizer_unittest.cc
@@ -56,7 +56,7 @@ class MockLayer : public Layer {
 
   virtual scoped_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl)
       OVERRIDE {
-    return MockLayerImpl::Create(tree_impl, layer_id_);
+    return MockLayerImpl::Create(tree_impl, layer_id_).PassAs<LayerImpl>();
   }
 
   virtual void PushPropertiesTo(LayerImpl* layer_impl) OVERRIDE {