add asAShadowBlur for android to drawlooper

src/core/SkDrawLooper.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkDrawLooper.h"
 #include "SkCanvas.h"
 #include "SkMatrix.h"
@@ skipping 41 matching lines @@
             if (firstTime) {
                 *dst = r;
             } else {
                 dst->join(r);
             }
         } else {
             break;
         }
     }
 }
+
+bool SkDrawLooper::asABlurShadow(BlurShadowRec*) const {
+    return false;
+}