bitmapshader with A8 bitmap should be colorized by the paint's color

include/core/SkShader.h

Index: include/core/SkShader.h
diff --git a/include/core/SkShader.h b/include/core/SkShader.h
index d0fac49f7e22cc30cbcb847c1538aada687fa18e..317633ff9f9042a201dba6d7ffc53728a8c7a982 100644
--- a/include/core/SkShader.h
+++ b/include/core/SkShader.h
@@ -345,6 +345,8 @@ public:
     static SkShader* CreateBitmapShader(const SkBitmap& src,
                                         TileMode tmx, TileMode tmy);
 
+    virtual SkBitmap* getBitmap() { return NULL;}

[bsalomon, 2014/03/13 14:59:04]

I don't think the Shader should expose a bitmap. If there isn't a way to deduce
this behavior from the Shader already then maybe the Shader subclass should have
explicit control of what part of the SkPaint's color it wants to use.

[yunchao, 2014/03/13 15:05:12]

What about expose an interface like this: bool isA8BitmapShader()? 

[yunchao, 2014/03/13 15:32:28]

Do you think it is unsafe if the shader expose a bitmap? I think check the
shader's bitmap config in skPaint2GrPaint() is appropriate. 

+
     SkDEVCODE(virtual void toString(SkString* str) const;)
 
     SK_DEFINE_FLATTENABLE_TYPE(SkShader)