Fix memory leak in SkSpecialSurface

src/core/SkSpecialSurface.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file
  */
 
 #include "SkCanvas.h"
 #include "SkSpecialImage.h"
 #include "SkSpecialSurface.h"
@@ skipping 36 matching lines @@
     SkASSERT(fSubset.height() > 0);
 }
 
 SkCanvas* SkSpecialSurface::getCanvas() {
     return as_SB(this)->onGetCanvas();
 }
 
 SkSpecialImage* SkSpecialSurface::newImageSnapshot() {
     SkSpecialImage* image = as_SB(this)->onNewImageSnapshot();
     as_SB(this)->reset();
-    return SkSafeRef(image);   // the caller will call unref() to balance this
+    return image;   // the caller gets the creation ref
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 #include "SkMallocPixelRef.h"
 
 class SkSpecialSurface_Raster : public SkSpecialSurface_Base {
 public:
     SkSpecialSurface_Raster(SkPixelRef* pr, const SkIRect& subset, const SkSurfaceProps* props)
         : INHERITED(subset, props) {   
         const SkImageInfo& info = pr->info();
@@ skipping 35 matching lines @@
 
 #if SK_SUPPORT_GPU
 ///////////////////////////////////////////////////////////////////////////////
 #include "GrContext.h"
 #include "SkGpuDevice.h"
 
 class SkSpecialSurface_Gpu : public SkSpecialSurface_Base {
 public:
     SkSpecialSurface_Gpu(GrTexture* texture, const SkIRect& subset, const SkSurfaceProps* props)
         : INHERITED(subset, props)
-        , fTexture(texture) {
+        , fTexture(SkRef(texture)) {
 
         SkASSERT(fTexture->asRenderTarget());
 
         SkAutoTUnref<SkGpuDevice> device(SkGpuDevice::Create(fTexture->asRenderTarget(), props,
                                                              SkGpuDevice::kUninit_InitContents));
         if (!device) {
             return;
         }
 
         fCanvas.reset(new SkCanvas(device));
@@ skipping 20 matching lines @@
     return new SkSpecialSurface_Gpu(texture, subset, props);
 }
 
 SkSpecialSurface* SkSpecialSurface::NewRenderTarget(GrContext* context,
                                                     const GrSurfaceDesc& desc,
                                                     const SkSurfaceProps* props) {
     if (!context || !SkToBool(desc.fFlags & kRenderTarget_GrSurfaceFlag)) {
         return nullptr;
     }
 
-    GrTexture* temp = context->textureProvider()->createApproxTexture(desc);
+    SkAutoTUnref<GrTexture> temp(context->textureProvider()->createApproxTexture(desc));
     if (!temp) {
         return nullptr;
     }
 
     const SkIRect subset = SkIRect::MakeWH(desc.fWidth, desc.fHeight);
 
     return new SkSpecialSurface_Gpu(temp, subset, props);
 }
 
 #else
 
 SkSpecialSurface* SkSpecialSurface::NewFromTexture(const SkIRect& subset, GrTexture*,
                                                    const SkSurfaceProps*) {
     return nullptr;
 }
 
 SkSpecialSurface* SkSpecialSurface::NewRenderTarget(GrContext* context,
                                                     const GrSurfaceDesc& desc,
                                                     const SkSurfaceProps* props) {
     return nullptr;
 }
 
 #endif