Alter SkCanvas::drawPicture (devirtualize, take const SkPicture, take pointer)

include/core/SkCanvas.h

Index: include/core/SkCanvas.h
diff --git a/include/core/SkCanvas.h b/include/core/SkCanvas.h
index 4aaf46b39703d33957098c0d98e1904b163808c1..a11ea2fd5b811ce95485edf5933ca3682d2d2635 100644
--- a/include/core/SkCanvas.h
+++ b/include/core/SkCanvas.h
@@ -969,13 +969,13 @@ public:
         drawPicture call.
         @param picture The recorded drawing commands to analyze/optimize
     */
-    void EXPERIMENTAL_optimize(SkPicture* picture);
+    void EXPERIMENTAL_optimize(const SkPicture* picture);
 
     /** PRIVATE / EXPERIMENTAL -- do not call
         Purge all the discardable optimization information associated with
         'picture'. If NULL is passed in, purge all discardable information.
     */
-    void EXPERIMENTAL_purge(SkPicture* picture);
+    void EXPERIMENTAL_purge(const SkPicture* picture);
 
     /** Draw the picture into this canvas. This method effective brackets the
         playback of the picture's draw calls with save/restore, so the state
@@ -983,7 +983,7 @@ public:
         @param picture The recorded drawing commands to playback into this
                        canvas.
     */
-    virtual void drawPicture(SkPicture& picture);
+    void drawPicture(const SkPicture* picture);
 
     enum VertexMode {
         kTriangles_VertexMode,
@@ -1242,6 +1242,8 @@ protected:
 
     virtual void onDiscard();
 
+    virtual void onDrawPicture(const SkPicture* picture);
+
     // Returns the canvas to be used by DrawIter. Default implementation
     // returns this. Subclasses that encapsulate an indirect canvas may
     // need to overload this method. The impl must keep track of this, as it