remove unused (by the outside) SkImage::newSurface, and simplify newImage -> newSubset

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_Gpu.h"
 
 #include "SkCanvas.h"
 #include "SkGpuDevice.h"
 #include "SkImage_Base.h"
 #include "SkImage_Gpu.h"
 #include "SkImagePriv.h"
 #include "SkSurface_Base.h"
 
 #if SK_SUPPORT_GPU
 
-///////////////////////////////////////////////////////////////////////////////
 SkSurface_Gpu::SkSurface_Gpu(SkGpuDevice* device)
     : INHERITED(device->width(), device->height(), &device->surfaceProps())
     , fDevice(SkRef(device)) {
 }
 
 SkSurface_Gpu::~SkSurface_Gpu() {
     fDevice->unref();
 }
 
 static GrRenderTarget* prepare_rt_for_external_access(SkSurface_Gpu* surface,
@@ skipping 43 matching lines @@
     GrRenderTarget* rt = fDevice->accessRenderTarget();
     int sampleCount = rt->numColorSamples();
     // TODO: Make caller specify this (change virtual signature of onNewSurface).
     static const Budgeted kBudgeted = kNo_Budgeted;
     return SkSurface::NewRenderTarget(fDevice->context(), kBudgeted, info, sampleCount,
                                       &this->props());
 }
 
 SkImage* SkSurface_Gpu::onNewImageSnapshot(Budgeted budgeted) {
     const SkImageInfo info = fDevice->imageInfo();
-    const int sampleCount = fDevice->accessRenderTarget()->numColorSamples();
     SkImage* image = nullptr;
     GrTexture* tex = fDevice->accessRenderTarget()->asTexture();
     if (tex) {
         image = new SkImage_Gpu(info.width(), info.height(), kNeedNewImageUniqueID,
-                                info.alphaType(), tex, sampleCount, budgeted);
+                                info.alphaType(), tex, budgeted);
     }
     if (image) {
         as_IB(image)->initWithProps(this->props());
     }
     return image;
 }
 
 // Create a new render target and, if necessary, copy the contents of the old
 // render target into it. Note that this flushes the SkGpuDevice but
 // doesn't force an OpenGL flush.
@@ skipping 69 matching lines @@
     }
     SkAutoTUnref<SkGpuDevice> device(SkGpuDevice::Create(rt, props,
                                                          SkGpuDevice::kUninit_InitContents));
     if (!device) {
         return nullptr;
     }
     return new SkSurface_Gpu(device);
 }
 
 #endif