In SkPixmap.cpp, change SkAlphaMul to SkMulDiv255.

include/core/SkCanvas.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkCanvas_DEFINED
 #define SkCanvas_DEFINED
 
@@ skipping 595 matching lines @@
      *  in the current clip with this color.
      */
     void clear(SkColor color) {
         this->drawColor(color, SkXfermode::kSrc_Mode);
     }
 
     /**
      * 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
      * to optimize performance on subsequent draws. Thus, if you call this and then
      * never draw to the canvas subsequently you may pay a perfomance penalty.
      */
     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
      */
     void drawPaint(const SkPaint& paint);
 
     enum PointMode {
         /** drawPoints draws each point separately */
         kPoints_PointMode,
         /** drawPoints draws each pair of points as a line segment */
         kLines_PointMode,
@@ skipping 939 matching lines @@
 
 class SkCanvasClipVisitor {
 public:
     virtual ~SkCanvasClipVisitor();
     virtual void clipRect(const SkRect&, SkRegion::Op, bool antialias) = 0;
     virtual void clipRRect(const SkRRect&, SkRegion::Op, bool antialias) = 0;
     virtual void clipPath(const SkPath&, SkRegion::Op, bool antialias) = 0;
 };
 
 #endif