gpu: Compositor management of GpuMemoryBuffer instances.

ui/gl/gl_image_shared_memory.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 "ui/gl/gl_image_shared_memory.h"
 
 #include "base/logging.h"
 #include "base/process/process_handle.h"
 
 namespace gfx {
 
 GLImageSharedMemory::GLImageSharedMemory(const gfx::Size& size,
                                          unsigned internalformat)
     : GLImageMemory(size, internalformat) {
 }
 
 GLImageSharedMemory::~GLImageSharedMemory() {
   DCHECK(!shared_memory_);
 }
 
-bool GLImageSharedMemory::Initialize(const gfx::GpuMemoryBufferHandle& handle) {
-  if (!HasValidFormat())
-    return false;
-
+bool GLImageSharedMemory::Initialize(const gfx::GpuMemoryBufferHandle& handle,
+                                     gfx::GpuMemoryBuffer::Format format) {
   if (!base::SharedMemory::IsHandleValid(handle.handle))
     return false;
 
   base::SharedMemory shared_memory(handle.handle, true);
 
   // Duplicate the handle.
   base::SharedMemoryHandle duped_shared_memory_handle;
   if (!shared_memory.ShareToProcess(base::GetCurrentProcessHandle(),
                                     &duped_shared_memory_handle)) {
     DVLOG(0) << "Failed to duplicate shared memory handle.";
     return false;
   }
 
   scoped_ptr<base::SharedMemory> duped_shared_memory(
       new base::SharedMemory(duped_shared_memory_handle, true));
+  if (!duped_shared_memory->Map(GetSize().GetArea() * BytesPerPixel(format))) {

[piman, 2014/10/09 21:33:02]

We should avoid GetSize().GetArea() * BytesPerPixel(format) because of potential
for overflow. We can use CheckedNumeric types like in e.g.
SharedBitmap::CheckedSizeInBytes to be safe (I realize you're just moving code,
but catching this now).

[reveman, 2014/10/10 02:20:16]

Done.

+    DVLOG(0) << "Failed to map shared memory.";
+    return false;
+  }
 
-  if (!duped_shared_memory->Map(Bytes())) {
-    DVLOG(0) << "Failed to map shared memory.";
+  if (!GLImageMemory::Initialize(
+          static_cast<unsigned char*>(duped_shared_memory->memory()), format)) {
     return false;
   }
 
   DCHECK(!shared_memory_);
   shared_memory_ = duped_shared_memory.Pass();
-  GLImageMemory::Initialize(
-      static_cast<unsigned char*>(shared_memory_->memory()));
   return true;
 }
 
 void GLImageSharedMemory::Destroy(bool have_context) {
   GLImageMemory::Destroy(have_context);
   shared_memory_.reset();
 }
 
 }  // namespace gfx