add support for new bitmapshader context

src/core/SkShader.cpp

 /*
  * 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.
  */
 
 #include "SkAtomics.h"
 #include "SkBitmapProcShader.h"
 #include "SkColorShader.h"
@@ skipping 68 matching lines @@
         colorPtr = &storage;
     }
     if (this->onAsLuminanceColor(colorPtr)) {
         *colorPtr = SkColorSetA(*colorPtr, 0xFF);   // we only return opaque
         return true;
     }
     return false;
 }
 
 SkShader::Context* SkShader::createContext(const ContextRec& rec, void* storage) const {
+    // We currently require 16byte alignment for some of our subclasses, so assert that here.
+    SkASSERT(SkIsAlign16((intptr_t)storage));
+
     if (!this->computeTotalInverse(rec, nullptr)) {
         return nullptr;
     }
     return this->onCreateContext(rec, storage);
 }
 
 SkShader::Context* SkShader::onCreateContext(const ContextRec& rec, void*) const {
     return nullptr;
 }
 
@@ skipping 266 matching lines @@
 #include "SkEmptyShader.h"
 
 void SkEmptyShader::toString(SkString* str) const {
     str->append("SkEmptyShader: (");
 
     this->INHERITED::toString(str);
 
     str->append(")");
 }
 #endif