Remove duplicate typedef

ui/gfx/canvas_paint_mac.mm

 // Copyright (c) 2012 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.
 
 #include "ui/gfx/canvas_paint_mac.h"
 #include "ui/gfx/geometry/size.h"
 
 namespace gfx {
 
 CanvasSkiaPaint::CanvasSkiaPaint(NSRect dirtyRect)
@@ skipping 42 matching lines @@
 void CanvasSkiaPaint::Init(bool opaque) {
   CGContextRef destination_context =
         (CGContextRef)[[NSGraphicsContext currentContext] graphicsPort];
   CGRect scaled_unit_rect = CGContextConvertRectToDeviceSpace(
         destination_context, CGRectMake(0, 0, 1, 1));
     // Assume that the x scale and the y scale are the same.
   CGFloat scale = scaled_unit_rect.size.width;
 
   gfx::Size size(NSWidth(rectangle_), NSHeight(rectangle_));
   RecreateBackingCanvas(size, scale, opaque);
-  skia::PlatformCanvas* canvas = platform_canvas();
+  SkCanvas* canvas = sk_canvas();

[f(malita), 2016/01/27 20:16:12]

Nit: this looks like a functional change, even though it isn't (sk_canvas() &
platform_canvas() point to the same thing, per our earlier conversation).

Let's leave the platform_canvas->sk_canvas switch for the CL which consolidates
the two.

   canvas->clear(SkColorSetARGB(0, 0, 0, 0));
 
     // Need to translate so that the dirty region appears at the origin of the
     // surface.
   canvas->translate(-SkDoubleToScalar(NSMinX(rectangle_)),
                     -SkDoubleToScalar(NSMinY(rectangle_)));
 
   context_ = skia::GetBitmapContext(*canvas);
 }
 
 }  // namespace skia