mus: Get GpuMemoryBuffer from gpu process when possible.

services/ui/common/mus_gpu_memory_buffer_manager.cc

Index: services/ui/common/mus_gpu_memory_buffer_manager.cc
diff --git a/services/ui/common/mus_gpu_memory_buffer_manager.cc b/services/ui/common/mus_gpu_memory_buffer_manager.cc
index eda17128a87cb968ce167c3838b2a190645d5b17..b51a8daba48f94bcc60cb7709c6503562c59cea6 100644
--- a/services/ui/common/mus_gpu_memory_buffer_manager.cc
+++ b/services/ui/common/mus_gpu_memory_buffer_manager.cc
@@ -19,34 +19,49 @@ MusGpuMemoryBufferManager::MusGpuMemoryBufferManager(
 
 MusGpuMemoryBufferManager::~MusGpuMemoryBufferManager() {}
 
-std::unique_ptr<gfx::GpuMemoryBuffer>
-MusGpuMemoryBufferManager::CreateGpuMemoryBuffer(
+gfx::GpuMemoryBufferHandle
+MusGpuMemoryBufferManager::CreateGpuMemoryBufferHandle(
+    gfx::GpuMemoryBufferId id,
+    int client_id,
     const gfx::Size& size,
     gfx::BufferFormat format,
     gfx::BufferUsage usage,
     gpu::SurfaceHandle surface_handle) {
   DCHECK(CalledOnValidThread());
-  gfx::GpuMemoryBufferId id(next_gpu_memory_id_++);
+  if (gpu::GetNativeGpuMemoryBufferType() == gfx::EMPTY_BUFFER)
+    return gfx::GpuMemoryBufferHandle();
   const bool is_native =
       gpu::IsNativeGpuMemoryBufferConfigurationSupported(format, usage);
   if (is_native) {
     gfx::GpuMemoryBufferHandle handle;
-    gpu_service_->CreateGpuMemoryBuffer(id, size, format, usage, client_id_,
+    gpu_service_->CreateGpuMemoryBuffer(id, size, format, usage, client_id,
                                         surface_handle, &handle);
-    if (handle.is_null())
-      return nullptr;
-    return gpu::GpuMemoryBufferImpl::CreateFromHandle(
-        handle, size, format, usage,
-        base::Bind(&MusGpuMemoryBufferManager::DestroyGpuMemoryBuffer,
-                   weak_factory_.GetWeakPtr(), id, client_id_, is_native));
+    if (!handle.is_null())
+      native_buffers_[client_id].insert(handle.id);
+    return handle;
   }
 
   DCHECK(gpu::GpuMemoryBufferImplSharedMemory::IsUsageSupported(usage))
       << static_cast<int>(usage);
-  return gpu::GpuMemoryBufferImplSharedMemory::Create(
-      id, size, format,
+  return gpu::GpuMemoryBufferImplSharedMemory::CreateGpuMemoryBuffer(id, size,
+                                                                     format);
+}
+
+std::unique_ptr<gfx::GpuMemoryBuffer>
+MusGpuMemoryBufferManager::CreateGpuMemoryBuffer(
+    const gfx::Size& size,
+    gfx::BufferFormat format,
+    gfx::BufferUsage usage,
+    gpu::SurfaceHandle surface_handle) {
+  gfx::GpuMemoryBufferId id(next_gpu_memory_id_++);
+  gfx::GpuMemoryBufferHandle handle = CreateGpuMemoryBufferHandle(
+      id, client_id_, size, format, usage, surface_handle);
+  if (handle.is_null())
+    return nullptr;
+  return gpu::GpuMemoryBufferImpl::CreateFromHandle(
+      handle, size, format, usage,
       base::Bind(&MusGpuMemoryBufferManager::DestroyGpuMemoryBuffer,
-                 weak_factory_.GetWeakPtr(), id, client_id_, is_native));
+                 weak_factory_.GetWeakPtr(), id, client_id_));
 }
 
 std::unique_ptr<gfx::GpuMemoryBuffer>
@@ -69,12 +84,24 @@ void MusGpuMemoryBufferManager::SetDestructionSyncToken(
 void MusGpuMemoryBufferManager::DestroyGpuMemoryBuffer(
     gfx::GpuMemoryBufferId id,
     int client_id,
-    bool is_native,
     const gpu::SyncToken& sync_token) {
   DCHECK(CalledOnValidThread());
-  if (is_native) {
-    gpu_service_->DestroyGpuMemoryBuffer(id, client_id, sync_token);
-  }
+  if (!native_buffers_.count(client_id) ||

[reveman, 2016/12/02 19:12:51]

nit: Do we need to check that the client_id exists? What's the harm of assuming
that it exists?

[sadrul, 2016/12/03 03:28:36]

We end up creating an empty map here if the client_id did not already exist. But
I suppose since we clear the map anyway when the client goes away, this would
not be a problem. Removed.

btw: both find [1] and count [2] have constant complexity on average.

[1] http://en.cppreference.com/w/cpp/container/unordered_map/find
[2] http://en.cppreference.com/w/cpp/container/unordered_map/count

+      !native_buffers_[client_id].erase(id))
+    return;
+  if (native_buffers_[client_id].empty())
+    native_buffers_.erase(client_id);

[reveman, 2016/12/02 19:12:51]

nit: We don't need these two lines anymore now that we notify the manager when a
client is gone, right?

[sadrul, 2016/12/03 03:28:35]

Yep. Removed.

+  gpu_service_->DestroyGpuMemoryBuffer(id, client_id, sync_token);
+}
+
+void MusGpuMemoryBufferManager::DestroyAllGpuMemoryBufferForClient(
+    int client_id) {
+  DCHECK(CalledOnValidThread());
+  if (!native_buffers_.count(client_id))

[reveman, 2016/12/02 19:12:51]

nit: This check seems like an unnecessary optimization

[sadrul, 2016/12/03 03:28:35]

Removed.

+    return;
+  for (gfx::GpuMemoryBufferId id : native_buffers_[client_id])
+    gpu_service_->DestroyGpuMemoryBuffer(id, client_id, gpu::SyncToken());
+  native_buffers_.erase(client_id);
 }
 
 }  // namespace ui