Clean up SkImageFilter constructors.

src/effects/SkMergeImageFilter.cpp

 /*
  * Copyright 2012 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 "SkMergeImageFilter.h"
 #include "SkCanvas.h"
 #include "SkDevice.h"
@@ skipping 22 matching lines @@
         this->initAllocModes();
         int inputCount = countInputs();
         for (int i = 0; i < inputCount; ++i) {
             fModes[i] = SkToU8(modes[i]);
         }
     } else {
         fModes = NULL;
     }
 }
 
-SkMergeImageFilter::SkMergeImageFilter(SkImageFilter* first, SkImageFilter* second,
-                                       SkXfermode::Mode mode,
-                                       const CropRect* cropRect) : INHERITED(first, second, cropRect) {
-    if (SkXfermode::kSrcOver_Mode != mode) {
-        SkXfermode::Mode modes[] = { mode, mode };
-        this->initModes(modes);
-    } else {
-        fModes = NULL;
-    }
-}
-
 SkMergeImageFilter::SkMergeImageFilter(SkImageFilter* filters[], int count,
                                        const SkXfermode::Mode modes[],
                                        const CropRect* cropRect) : INHERITED(count, filters, cropRect) {
     SkASSERT(count >= 0);
     this->initModes(modes);
 }
 
 SkMergeImageFilter::~SkMergeImageFilter() {
 
     if (fModes != SkTCast<uint8_t*>(fStorage)) {
@@ skipping 72 matching lines @@
         if (buffer.validate(buffer.getArrayCount() == size) &&
             buffer.readByteArray(fModes, size)) {
             for (int i = 0; i < nbInputs; ++i) {
                 buffer.validate(SkIsValidMode((SkXfermode::Mode)fModes[i]));
             }
         }
     } else {
         fModes = 0;
     }
 }