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

Review URL: https://codereview.chromium.org/609663003

Cr-Commit-Position: refs/heads/master@{#297096}

1 files changed, 1 insertions, 1 deletions

diff --git a/cc/surfaces/surface_aggregator.cc b/cc/surfaces/surface_aggregator.cc
index 679d751..35107e8 100644
--- a/cc/surfaces/surface_aggregator.cc
+++ b/cc/surfaces/surface_aggregator.cc
@@ -355,7 +355,7 @@ scoped_ptr<CompositorFrame> SurfaceAggregator::Aggregate(SurfaceId surface_id) {
   contained_surfaces_[surface_id] = surface->frame_index();
   const CompositorFrame* root_surface_frame = surface->GetEligibleFrame();
   if (!root_surface_frame)
-    return scoped_ptr<CompositorFrame>();
+    return nullptr;
   TRACE_EVENT0("cc", "SurfaceAggregator::Aggregate");
 
   scoped_ptr<CompositorFrame> frame(new CompositorFrame);