Replace setMatrixClip() with BeginPlatformPaint() logic

skia/ext/platform_canvas.h

 // 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.
 
 #ifndef SKIA_EXT_PLATFORM_CANVAS_H_
 #define SKIA_EXT_PLATFORM_CANVAS_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 122 matching lines @@
 // Gives the pixmap passed in *writable* access to the pixels backing this
 // canvas. All writes to the pixmap should be visible if the canvas is
 // raster-backed.
 //
 // Returns false on failure: if either argument is nullptr, or if the
 // pixels can not be retrieved from the canvas. In the latter case resets
 // the pixmap to empty.
 SK_API bool GetWritablePixels(SkCanvas* canvas, SkPixmap* pixmap);
 
 // Returns true if native platform routines can be used to draw on the
-// given canvas. If this function returns false, BeginPlatformPaint will
-// return NULL PlatformSurface.
+// given canvas. If this function returns false,
+// ScopedPlatformPaint::GetPlatformSurface() should return NULL.
 SK_API bool SupportsPlatformPaint(const SkCanvas* canvas);
 
 // This object guards calls to platform drawing routines. The surface
 // returned from GetPlatformSurface() can be used with the native platform
 // routines.
 class SK_API ScopedPlatformPaint {
  public:
   explicit ScopedPlatformPaint(SkCanvas* canvas);
 
   // Returns the PlatformSurface to use for native platform drawing calls.
@@ skipping 17 matching lines @@
 SK_API bool IsPreviewMetafile(const SkCanvas& canvas);
 
 // Returns the CGContext that backing the SkCanvas.
 // Returns NULL if none is bound.
 SK_API CGContextRef GetBitmapContext(const SkCanvas& canvas);
 #endif
 
 }  // namespace skia
 
 #endif  // SKIA_EXT_PLATFORM_CANVAS_H_