mac: Fix a memory leak in canvas_skia_mac.

ui/gfx/canvas_skia_mac.mm

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import <Cocoa/Cocoa.h>
 
 #include "ui/gfx/canvas_skia.h"
 
 #include "base/mac/mac_util.h"
 #include "base/mac/scoped_cftyperef.h"
@@ skipping 49 matching lines @@
           nil];
 
   NSAttributedString* ns_string =
       [[[NSAttributedString alloc] initWithString:base::SysUTF16ToNSString(text)
                                        attributes:attributes] autorelease];
   base::mac::ScopedCFTypeRef<CTFramesetterRef> framesetter(
       CTFramesetterCreateWithAttributedString(
           base::mac::NSToCFCast(ns_string)));
 
   CGRect text_bounds = CGRectMake(x, y, w, h);
-  CGMutablePathRef path = CGPathCreateMutable();
+  base::mac::ScopedCFTypeRef<CGMutablePathRef> path(CGPathCreateMutable());
   CGPathAddRect(path, NULL, text_bounds);
 
   base::mac::ScopedCFTypeRef<CTFrameRef> frame(
       CTFramesetterCreateFrame(framesetter, CFRangeMake(0, 0), path, NULL));
   CTFrameDraw(frame, context);
   CGContextRestoreGState(context);
 }
 
 ui::TextureID CanvasSkia::GetTextureID() {
   // TODO(wjmaclean)
   return 0;
 }
 
 }  // namespace gfx