Clean up SkImageFilter constructors.

src/effects/SkXfermodeImageFilter.cpp

 /*
  * Copyright 2013 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 "SkXfermodeImageFilter.h"
 #include "SkCanvas.h"
 #include "SkDevice.h"
 #include "SkColorPriv.h"
 #include "SkReadBuffer.h"
 #include "SkWriteBuffer.h"
 #include "SkXfermode.h"
 #if SK_SUPPORT_GPU
 #include "GrContext.h"
 #include "effects/GrSimpleTextureEffect.h"
 #include "SkGr.h"
 #endif
 
 ///////////////////////////////////////////////////////////////////////////////
 
 SkXfermodeImageFilter::SkXfermodeImageFilter(SkXfermode* mode,
-                                             SkImageFilter* background,
-                                             SkImageFilter* foreground,
+                                             SkImageFilter* inputs[2],
                                              const CropRect* cropRect)
-  : INHERITED(background, foreground, cropRect), fMode(mode) {
+  : INHERITED(2, inputs, cropRect), fMode(mode) {
     SkSafeRef(fMode);
 }
 
 SkXfermodeImageFilter::~SkXfermodeImageFilter() {
     SkSafeUnref(fMode);
 }
 
 SkXfermodeImageFilter::SkXfermodeImageFilter(SkReadBuffer& buffer)
   : INHERITED(2, buffer) {
     fMode = buffer.readXfermode();
@@ skipping 118 matching lines @@
     paint.addColorEffect(xferEffect)->unref();
     context->drawRect(paint, srcRect);
 
     offset->fX = backgroundOffset.fX;
     offset->fY = backgroundOffset.fY;
     WrapTexture(dst, src.width(), src.height(), result);
     return true;
 }
 
 #endif