Revert of change all factories to return their base-class

include/effects/SkBlurDrawLooper.h

 /*
  * Copyright 2008 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 SkBlurDrawLooper_DEFINED
 #define SkBlurDrawLooper_DEFINED
@@ skipping 17 matching lines @@
             The blur layer's dx/dy/radius aren't affected by the canvas
             transform.
         */
         kIgnoreTransform_BlurFlag   = 0x01,
         kOverrideColor_BlurFlag     = 0x02,
         kHighQuality_BlurFlag       = 0x04,
         /** mask for all blur flags */
         kAll_BlurFlag               = 0x07
     };
 
-    static SkDrawLooper* Create(SkColor color, SkScalar sigma, SkScalar dx, SkScalar dy,
-                                uint32_t flags = kNone_BlurFlag) {
+    static SkBlurDrawLooper* Create(SkColor color, SkScalar sigma, SkScalar dx, SkScalar dy,
+                                    uint32_t flags = kNone_BlurFlag) {
         return new SkBlurDrawLooper(color, sigma, dx, dy, flags);
     }
 
     virtual ~SkBlurDrawLooper();
 
     SkDrawLooper::Context* createContext(SkCanvas*, void* storage) const override;
 
     size_t contextSize() const override { return sizeof(BlurDrawLooperContext); }
 
     SK_TO_STRING_OVERRIDE()
@@ skipping 31 matching lines @@
         State fState;
     };
 
     void init(SkScalar sigma, SkScalar dx, SkScalar dy, SkColor color, uint32_t flags);
     void initEffects();
 
     typedef SkDrawLooper INHERITED;
 };
 
 #endif