use new instead of createCompatibleDevice, since we know the subclass we want

src/image/SkSurface_Gpu.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkSurface_Base.h"
 #include "SkImagePriv.h"
 #include "SkCanvas.h"
@@ skipping 67 matching lines @@
 }
 
 // Create a new SkGpuDevice and, if necessary, copy the contents of the old
 // device into it. Note that this flushes the SkGpuDevice but
 // doesn't force an OpenGL flush.
 void SkSurface_Gpu::onCopyOnWrite(ContentChangeMode mode) {
     GrRenderTarget* rt = fDevice->accessRenderTarget();
     // are we sharing our render target with the image?
     SkASSERT(NULL != this->getCachedImage());
     if (rt->asTexture() == SkTextureImageGetTexture(this->getCachedImage())) {
-        SkGpuDevice* newDevice = static_cast<SkGpuDevice*>(
-            fDevice->createCompatibleDevice(fDevice->config(), fDevice->width(),
-            fDevice->height(), fDevice->isOpaque()));
-        SkAutoTUnref<SkGpuDevice> aurd(newDevice);
+        SkAutoTUnref<SkGpuDevice> newDevice(SkNEW_ARGS(SkGpuDevice,
+            (fDevice->context(), fDevice->config(), fDevice->width(),
+             fDevice->height(), rt->numSamples())));
+
         if (kRetain_ContentChangeMode == mode) {
             fDevice->context()->copyTexture(rt->asTexture(),
                 reinterpret_cast<GrRenderTarget*>(newDevice->accessRenderTarget()));
         }
         SkASSERT(NULL != this->getCachedCanvas());
         SkASSERT(this->getCachedCanvas()->getDevice() == fDevice);
         this->getCachedCanvas()->setDevice(newDevice);
-        SkRefCnt_SafeAssign(fDevice, newDevice);
+        SkRefCnt_SafeAssign(fDevice, newDevice.get());
     }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 SkSurface* SkSurface::NewRenderTargetDirect(GrRenderTarget* target) {
     if (NULL == target) {
         return NULL;
     }
     return SkNEW_ARGS(SkSurface_Gpu, (target));
@@ skipping 21 matching lines @@
     desc.fConfig = SkBitmapConfig2GrPixelConfig(config);
     desc.fSampleCnt = sampleCount;
 
     SkAutoTUnref<GrTexture> tex(ctx->createUncachedTexture(desc, NULL, 0));
     if (NULL == tex) {
         return NULL;
     }
 
     return SkNEW_ARGS(SkSurface_Gpu, (tex->asRenderTarget()));
 }