Implement rewrite logic for assigning a temporary scoped_refptr to T*.

This is always potentially dangerous. For example:
scoped_refptr<Foo> CreateFoo();
void BuggyFunction() {
  Foo* x = CreateFoo();
  // x now points to a deleted object.
}
In these cases, the tool prefers to rewrite the declaration type to
scoped_refptr<T> instead of adding an explicit conversion to T* with
get().

BUG=110610
R=mdempsky@chromium.org, rsleevi@chromium.org

Review URL: https://codereview.chromium.org/453873002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288795 0039d316-1c4b-4281-b951-d872f2087c98
19 files changed