Fix memory leaks reported by clang static analyzer.

The CFURLCopyFileSystemPath & CFURLCopyFileSystemPath methods
respect the "Create Rule" [1] regarding the ownership of the
returned reference. This means that the objects need to be
deallocated explicitly by calling CFRelease.

[1]: https://developer.apple.com/library/content/documentation/CoreFoundation/Conceptual/CFMemoryMgmt/Concepts/Ownership.html#//apple_ref/doc/uid/20001148-103029

BUG=648210
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2360573002

Review-Url: https://codereview.chromium.org/2360573002
1 file changed