enforce 16byte alignment in shader contexts

include/core/SkShader.h

Index: include/core/SkShader.h
diff --git a/include/core/SkShader.h b/include/core/SkShader.h
index 0645809fe6873a9acbc6190895f109a83b8ea465..828467fec237ee07e8d086945d85049827e6c55f 100644
--- a/include/core/SkShader.h
+++ b/include/core/SkShader.h
@@ -192,11 +192,8 @@ public:
 
     /**
      *  Return the size of a Context returned by createContext.
-     *
-     *  Override this if your subclass overrides createContext, to return the correct size of
-     *  your subclass' context.
      */
-    virtual size_t contextSize(const ContextRec&) const;
+    size_t contextSize(const ContextRec&) const;
 
     /**
      *  Returns true if this shader is just a bitmap, and if not null, returns the bitmap,
@@ -420,6 +417,12 @@ protected:
      */
     virtual Context* onCreateContext(const ContextRec&, void* storage) const;
 
+    /**
+     *  Override this if your subclass overrides createContext, to return the correct size of
+     *  your subclass' context.
+     */
+    virtual size_t onContextSize(const ContextRec&) const;
+
     virtual bool onAsLuminanceColor(SkColor*) const {
         return false;
     }