Update use of SkCanvas and SkDevice to match change in Skia

skia/ext/bitmap_platform_device_mac.h

Index: skia/ext/bitmap_platform_device_mac.h
diff --git a/skia/ext/bitmap_platform_device_mac.h b/skia/ext/bitmap_platform_device_mac.h
index 195dca866ae9f6417b4ac76a8daa76339777c0b9..68c717ce3b309c9e039058303c80244e4065e262 100644
--- a/skia/ext/bitmap_platform_device_mac.h
+++ b/skia/ext/bitmap_platform_device_mac.h
@@ -10,6 +10,13 @@
 
 namespace skia {
 
+class SkBitmapPlatformDeviceFactory : public SkRasterDeviceFactory {
+ public:
+  virtual SkDevice* newDevice(SkBitmap::Config config, int width, int height,
+                              bool isOpaque, bool isForLayer);
+};
+
+
 // A device is basically a wrapper around SkBitmap that provides a surface for
 // SkCanvas to draw into. Our device provides a surface CoreGraphics can also
 // write to. BitmapPlatformDevice creates a bitmap using
@@ -50,6 +57,10 @@ class BitmapPlatformDevice : public PlatformDevice {
   BitmapPlatformDevice(const BitmapPlatformDevice& other);
   virtual ~BitmapPlatformDevice();
 
+  virtual SkDeviceFactory* getDeviceFactory() {
+    return SkNEW(SkBitmapPlatformDeviceFactory);
+  }
+
   // See warning for copy constructor above.
   BitmapPlatformDevice& operator=(const BitmapPlatformDevice& other);