keep only one typedef for the native drawing context

skia/ext/platform_canvas.cc

 // 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.
 
 #include "skia/ext/platform_canvas.h"
 
 #include "base/logging.h"
 #include "build/build_config.h"
 #include "skia/ext/platform_device.h"
 #include "third_party/skia/include/core/SkMetaData.h"
@@ skipping 87 matching lines @@
   return platform_device ?
       platform_device->GetBitmapContext(
           canvas.getTotalMatrix(), clip_bounds) :
       nullptr;
 }
 
 #endif
 
 ScopedPlatformPaint::ScopedPlatformPaint(SkCanvas* canvas) :
     canvas_(canvas),
-    platform_surface_(nullptr) {
+    native_drawing_context_(nullptr) {
   // TODO(tomhudson) we're assuming non-null canvas?
   PlatformDevice* platform_device = GetPlatformDevice(canvas->getTopDevice(true));
   if (platform_device) {
     // Compensate for drawing to a layer rather than the entire canvas
     SkMatrix ctm;
     SkIRect clip_bounds;
     canvas->temporary_internal_describeTopLayer(&ctm, &clip_bounds);
-    platform_surface_ = platform_device->BeginPlatformPaint(ctm, clip_bounds);
+    native_drawing_context_ = platform_device->BeginPlatformPaint(ctm, clip_bounds);
   }
 }
 
 }  // namespace skia