In SkPixmap.cpp, change SkAlphaMul to SkMulDiv255.

include/core/SkCanvas.h

Index: include/core/SkCanvas.h
diff --git a/include/core/SkCanvas.h b/include/core/SkCanvas.h
index 33d565c0a186bbcf40df69f1be8b95e4bfb8b4a9..14f0aa5250920aded9f78b9a541e2b2857cd454b 100644
--- a/include/core/SkCanvas.h
+++ b/include/core/SkCanvas.h
@@ -613,8 +613,8 @@ public:
      * This makes the contents of the canvas undefined. Subsequent calls that
      * require reading the canvas contents will produce undefined results. Examples
      * include blending and readPixels. The actual implementation is backend-
-     * dependent and one legal implementation is to do nothing. Like clear(), this
-     * ignores the clip.
+     * dependent and one legal implementation is to do nothing. This method
+     * ignores the current clip.
      *
      * This function should only be called if the caller intends to subsequently
      * draw to the canvas. The canvas may do real work at discard() time in order
@@ -624,7 +624,7 @@ public:
     void discard() { this->onDiscard(); }
 
     /**
-     *  Fill the entire canvas' bitmap (restricted to the current clip) with the
+     *  Fill the entire canvas (restricted to the current clip) with the
      *  specified paint.
      *  @param paint    The paint used to fill the canvas
      */