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}

1 files changed, 6 insertions, 3 deletions

diff --git a/cc/layers/texture_layer_unittest.cc b/cc/layers/texture_layer_unittest.cc
index b3c48fb..feb7126 100644
--- a/cc/layers/texture_layer_unittest.cc
+++ b/cc/layers/texture_layer_unittest.cc
@@ -185,7 +185,7 @@ class TextureLayerTest : public testing::Test {
     EXPECT_CALL(*layer_tree_host_, SetNeedsCommit()).Times(AnyNumber());
 
     layer_tree_host_->SetRootLayer(NULL);
-    layer_tree_host_ = nullptr;
+    layer_tree_host_.reset();
   }
 
   scoped_ptr<MockLayerTreeHost> layer_tree_host_;
@@ -422,7 +422,9 @@ class TextureLayerMailboxHolderTest : public TextureLayerTest {
         SingleReleaseCallback::Create(test_data_.release_mailbox1_)).Pass();
   }
 
-  void ReleaseMainRef() { main_ref_ = nullptr; }
+  void ReleaseMainRef() {
+    main_ref_.reset();
+  }
 
   void CreateImplRef(scoped_ptr<SingleReleaseCallbackImpl>* impl_ref) {
     *impl_ref = main_ref_->holder()->GetCallbackForImplThread();
@@ -930,7 +932,8 @@ class TextureLayerImplWithMailboxTest : public TextureLayerTest {
   virtual void SetUp() {
     TextureLayerTest::SetUp();
     layer_tree_host_.reset(new MockLayerTreeHost(&fake_client_));
-    EXPECT_TRUE(host_impl_.InitializeRenderer(FakeOutputSurface::Create3d()));
+    EXPECT_TRUE(host_impl_.InitializeRenderer(
+        FakeOutputSurface::Create3d().PassAs<OutputSurface>()));
   }
 
   bool WillDraw(TextureLayerImpl* layer, DrawMode mode) {