switch GatherPixelRefs to use SkBaseDevice instead of SkBitmapDevice

src/core/SkBitmapDevice.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 "SkBitmapDevice.h"
 #include "SkConfig8888.h"
 #include "SkDraw.h"
@@ skipping 59 matching lines @@
         fBitmap.lockPixels();
     }
 }
 
 void SkBitmapDevice::unlockPixels() {
     if (fBitmap.lockPixelsAreWritable()) {
         fBitmap.unlockPixels();
     }
 }
 
-void SkBitmapDevice::getGlobalBounds(SkIRect* bounds) const {
-    if (NULL != bounds) {
-        const SkIPoint& origin = this->getOrigin();
-        bounds->setXYWH(origin.x(), origin.y(),
-                        fBitmap.width(), fBitmap.height());
-    }
-}
-
 void SkBitmapDevice::clear(SkColor color) {
     fBitmap.eraseColor(color);
 }
 
 const SkBitmap& SkBitmapDevice::onAccessBitmap() {
     return fBitmap;
 }
 
 bool SkBitmapDevice::canHandleImageFilter(SkImageFilter*) {
     return false;
@@ skipping 307 matching lines @@
         paint.getStyle() != SkPaint::kFill_Style ||
         !SkXfermode::IsMode(paint.getXfermode(), SkXfermode::kSrcOver_Mode)) {
         // turn off lcd
         flags->fFlags = paint.getFlags() & ~SkPaint::kLCDRenderText_Flag;
         flags->fHinting = paint.getHinting();
         return true;
     }
     // we're cool with the paint as is
     return false;
 }