add drawPicture variant that takes a matrix and paint

include/core/SkCanvas.h

Index: include/core/SkCanvas.h
diff --git a/include/core/SkCanvas.h b/include/core/SkCanvas.h
index f74ebb7f56ff3a93f05efd89b72fdf4e79c4acc5..011e3c3a037dfd1bc1c18b525ef3f08772115aeb 100644
--- a/include/core/SkCanvas.h
+++ b/include/core/SkCanvas.h
@@ -973,6 +973,20 @@ public:
     */
     void drawPicture(const SkPicture* picture);
 
+    /**
+     *  Draw the picture into this canvas.
+     *
+     *  If matrix is non-null, apply that matrix to the CTM when drawing this picture. This is
+     *  logically equivalent to
+     *      save/concat/drawPicture/restore
+     *
+     *  If paint is non-null, draw the picture into a temporary buffer, and then apply the paint's
+     *  alpha/colorfilter/imagefilter/xfermode to that buffer as it is drawn to the canvas.
+     *  This is logically equivalent to
+     *      saveLayer(paint)/drawPicture/restore
+     */
+    void drawPicture(const SkPicture*, const SkMatrix* matrix, const SkPaint* paint);
+
     enum VertexMode {
         kTriangles_VertexMode,
         kTriangleStrip_VertexMode,
@@ -1223,7 +1237,7 @@ protected:
 
     virtual void onDiscard();
 
-    virtual void onDrawPicture(const SkPicture* picture);
+    virtual void onDrawPicture(const SkPicture*, const SkMatrix*, const SkPaint*);
 
     // Returns the canvas to be used by DrawIter. Default implementation
     // returns this. Subclasses that encapsulate an indirect canvas may