Replace setMatrixClip() with BeginPlatformPaint() logic

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 79 matching lines @@
   SetBoolMetaData(canvas, kIsPreviewMetafileKey, is_preview);
 }
 
 bool IsPreviewMetafile(const SkCanvas& canvas) {
   return GetBoolMetaData(canvas, kIsPreviewMetafileKey);
 }
 
 CGContextRef GetBitmapContext(const SkCanvas& canvas) {
   SkBaseDevice* device = GetTopDevice(canvas);
   PlatformDevice* platform_device = GetPlatformDevice(device);
-  return platform_device ?  platform_device->GetBitmapContext() :
+  SkIRect clip_bounds;
+  canvas.getClipDeviceBounds(&clip_bounds);
+  return platform_device ?
+      platform_device->GetBitmapContext(
+          canvas.getTotalMatrix(), clip_bounds) :
       nullptr;
 }
 
 #endif
 
 ScopedPlatformPaint::ScopedPlatformPaint(SkCanvas* canvas) :
     canvas_(canvas),
     platform_surface_(nullptr) {
+  // TODO(tomhudson) we're assuming non-null canvas?
   PlatformDevice* platform_device = GetPlatformDevice(GetTopDevice(*canvas));
-  if (platform_device)
-    platform_surface_ = platform_device->BeginPlatformPaint();
+  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);
+  }
 }
 
 }  // namespace skia