content: Cleanup IOSurface/SurfaceTexture destruction code.

content/common/gpu/gpu_memory_buffer_factory_io_surface.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/common/gpu/gpu_memory_buffer_factory_io_surface.h"
 
 #include <CoreFoundation/CoreFoundation.h>
 
 #include "base/logging.h"
 #include "ui/gl/gl_image_io_surface.h"
@@ skipping 128 matching lines @@
   handle.io_surface_id = IOSurfaceGetID(io_surface);
   return handle;
 }
 
 void GpuMemoryBufferFactoryIOSurface::DestroyGpuMemoryBuffer(
     gfx::GpuMemoryBufferId id,
     int client_id) {
   base::AutoLock lock(io_surfaces_lock_);
 
   IOSurfaceMapKey key(id, client_id);
-  IOSurfaceMap::iterator it = io_surfaces_.find(key);
-  if (it != io_surfaces_.end())
-    io_surfaces_.erase(it);
+  DCHECK(io_surfaces_.find(key) != io_surfaces_.end());
+  io_surfaces_.erase(key);
 }
 
 gpu::ImageFactory* GpuMemoryBufferFactoryIOSurface::AsImageFactory() {
   return this;
 }
 
 scoped_refptr<gfx::GLImage>
 GpuMemoryBufferFactoryIOSurface::CreateImageForGpuMemoryBuffer(
     const gfx::GpuMemoryBufferHandle& handle,
     const gfx::Size& size,
     gfx::GpuMemoryBuffer::Format format,
     unsigned internalformat,
     int client_id) {
   base::AutoLock lock(io_surfaces_lock_);
 
   DCHECK_EQ(handle.type, gfx::IO_SURFACE_BUFFER);
   IOSurfaceMapKey key(handle.id, client_id);
   IOSurfaceMap::iterator it = io_surfaces_.find(key);
   if (it == io_surfaces_.end())
     return scoped_refptr<gfx::GLImage>();
 
   scoped_refptr<gfx::GLImageIOSurface> image(new gfx::GLImageIOSurface(size));
   if (!image->Initialize(it->second.get()))
     return scoped_refptr<gfx::GLImage>();
 
   return image;
 }
 
 }  // namespace content