Add utility for converting SkCanvas to CGContext

skia/ext/skia_utils_mac.h

Index: skia/ext/skia_utils_mac.h
===================================================================
--- skia/ext/skia_utils_mac.h	(revision 85477)
+++ skia/ext/skia_utils_mac.h	(working copy)
@@ -15,6 +15,7 @@
 struct SkPoint;
 struct SkRect;
 class SkBitmap;
+class SkCanvas;
 class SkMatrix;
 #ifdef __LP64__
 typedef CGSize NSSize;
@@ -86,6 +87,20 @@
 // Returns |[NSImage imageNamed:@"NSApplicationIcon"]| as SkBitmap.
 SkBitmap AppplicationIconAtSize(int size);
 
+// Converts a SkCanvas temporarily to a CGContext
+class SkiaBitLocker {
+ public:
+  explicit SkiaBitLocker(SkCanvas* canvas);
+  ~SkiaBitLocker();
+  CGContextRef cgContext();
+
+ private:
+  void releaseIfNeeded();
+  SkCanvas* canvas_;
+  CGContextRef cgContext_;
+};
+
+
 }  // namespace gfx
 
 #endif  // SKIA_EXT_SKIA_UTILS_MAC_H_