change all factories to return their base-class

src/effects/SkEmbossMaskFilter.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 "SkEmbossMaskFilter.h"
 #include "SkBlurMaskFilter.h"
 #include "SkBlurMask.h"
 #include "SkEmbossMask.h"
 #include "SkReadBuffer.h"
 #include "SkWriteBuffer.h"
 #include "SkString.h"
 
-SkEmbossMaskFilter* SkEmbossMaskFilter::Create(SkScalar blurSigma, const Light& light) {
+SkMaskFilter* SkEmbossMaskFilter::Create(SkScalar blurSigma, const Light& light) {
     return new SkEmbossMaskFilter(blurSigma, light);
 }
 
 static inline int pin2byte(int n) {
     if (n < 0) {
         n = 0;
     } else if (n > 0xFF) {
         n = 0xFF;
     }
     return n;
@@ skipping 127 matching lines @@
     str->append(") ");
 
     str->appendf("ambient: %d specular: %d ",
         fLight.fAmbient, fLight.fSpecular);
 
     str->append("blurSigma: ");
     str->appendScalar(fBlurSigma);
     str->append(")");
 }
 #endif