content/browser/gpu/browser_gpu_channel_host_factory.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "content/browser/gpu/browser_gpu_channel_host_factory.h"
   6
   7 #include <set>
   8
   9 #include "base/bind.h"
  10 #include "base/profiler/scoped_tracker.h"
  11 #include "base/synchronization/waitable_event.h"
  12 #include "base/threading/thread_restrictions.h"
  13 #include "base/trace_event/trace_event.h"
  14 #include "content/browser/gpu/browser_gpu_memory_buffer_manager.h"
  15 #include "content/browser/gpu/gpu_data_manager_impl.h"
  16 #include "content/browser/gpu/gpu_process_host.h"
  17 #include "content/browser/gpu/gpu_surface_tracker.h"
  18 #include "content/common/child_process_host_impl.h"
  19 #include "content/common/gpu/gpu_memory_buffer_factory.h"
  20 #include "content/common/gpu/gpu_messages.h"
  21 #include "content/public/browser/browser_thread.h"
  22 #include "content/public/browser/gpu_data_manager.h"
  23 #include "content/public/common/content_client.h"
  24 #include "gpu/GLES2/gl2extchromium.h"
  25 #include "ipc/ipc_channel_handle.h"
  26 #include "ipc/ipc_forwarding_message_filter.h"
  27 #include "ipc/message_filter.h"
  28
  29 #if defined(OS_MACOSX)
  30 #include "content/common/gpu/gpu_memory_buffer_factory_io_surface.h"
  31 #endif
  32
  33 #if defined(OS_ANDROID)
  34 #include "content/common/gpu/gpu_memory_buffer_factory_surface_texture.h"
  35 #endif
  36
  37 #if defined(USE_OZONE)
  38 #include "content/common/gpu/gpu_memory_buffer_factory_ozone_native_buffer.h"
  39 #endif
  40
  41 namespace content {
  42 namespace {
  43
  44 base::LazyInstance<std::set<gfx::GpuMemoryBuffer::Usage>>
  45     g_enabled_gpu_memory_buffer_usages;
  46 }
  47
  48 BrowserGpuChannelHostFactory* BrowserGpuChannelHostFactory::instance_ = NULL;
  49
  50 struct BrowserGpuChannelHostFactory::CreateRequest {
  51   CreateRequest(int32 route_id)
  52       : event(true, false),
  53         gpu_host_id(0),
  54         route_id(route_id),
  55         result(CREATE_COMMAND_BUFFER_FAILED) {}
  56   ~CreateRequest() {}
  57   base::WaitableEvent event;
  58   int gpu_host_id;
  59   int32 route_id;
  60   CreateCommandBufferResult result;
  61 };
  62
  63 class BrowserGpuChannelHostFactory::EstablishRequest
  64     : public base::RefCountedThreadSafe<EstablishRequest> {
  65  public:
  66   static scoped_refptr<EstablishRequest> Create(CauseForGpuLaunch cause,
  67                                                 int gpu_client_id,
  68                                                 int gpu_host_id);
  69   void Wait();
  70   void Cancel();
  71
  72   int gpu_host_id() { return gpu_host_id_; }
  73   IPC::ChannelHandle& channel_handle() { return channel_handle_; }
  74   gpu::GPUInfo gpu_info() { return gpu_info_; }
  75
  76  private:
  77   friend class base::RefCountedThreadSafe<EstablishRequest>;
  78   explicit EstablishRequest(CauseForGpuLaunch cause,
  79                             int gpu_client_id,
  80                             int gpu_host_id);
  81   ~EstablishRequest() {}
  82   void EstablishOnIO();
  83   void OnEstablishedOnIO(const IPC::ChannelHandle& channel_handle,
  84                          const gpu::GPUInfo& gpu_info);
  85   void FinishOnIO();
  86   void FinishOnMain();
  87
  88   base::WaitableEvent event_;
  89   CauseForGpuLaunch cause_for_gpu_launch_;
  90   const int gpu_client_id_;
  91   int gpu_host_id_;
  92   bool reused_gpu_process_;
  93   IPC::ChannelHandle channel_handle_;
  94   gpu::GPUInfo gpu_info_;
  95   bool finished_;
  96   scoped_refptr<base::MessageLoopProxy> main_loop_;
  97 };
  98
  99 scoped_refptr<BrowserGpuChannelHostFactory::EstablishRequest>
 100 BrowserGpuChannelHostFactory::EstablishRequest::Create(CauseForGpuLaunch cause,
 101                                                        int gpu_client_id,
 102                                                        int gpu_host_id) {
 103   scoped_refptr<EstablishRequest> establish_request =
 104       new EstablishRequest(cause, gpu_client_id, gpu_host_id);
 105   scoped_refptr<base::MessageLoopProxy> loop =
 106       BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO);
 107   // PostTask outside the constructor to ensure at least one reference exists.
 108   loop->PostTask(
 109       FROM_HERE,
 110       base::Bind(&BrowserGpuChannelHostFactory::EstablishRequest::EstablishOnIO,
 111                  establish_request));
 112   return establish_request;
 113 }
 114
 115 BrowserGpuChannelHostFactory::EstablishRequest::EstablishRequest(
 116     CauseForGpuLaunch cause,
 117     int gpu_client_id,
 118     int gpu_host_id)
 119     : event_(false, false),
 120       cause_for_gpu_launch_(cause),
 121       gpu_client_id_(gpu_client_id),
 122       gpu_host_id_(gpu_host_id),
 123       reused_gpu_process_(false),
 124       finished_(false),
 125       main_loop_(base::MessageLoopProxy::current()) {
 126 }
 127
 128 void BrowserGpuChannelHostFactory::EstablishRequest::EstablishOnIO() {
 129   // TODO(pkasting): Remove ScopedTracker below once crbug.com/477117 is fixed.
 130   tracked_objects::ScopedTracker tracking_profile(
 131       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 132           "477117 "
 133           "BrowserGpuChannelHostFactory::EstablishRequest::EstablishOnIO"));
 134   GpuProcessHost* host = GpuProcessHost::FromID(gpu_host_id_);
 135   if (!host) {
 136     host = GpuProcessHost::Get(GpuProcessHost::GPU_PROCESS_KIND_SANDBOXED,
 137                                cause_for_gpu_launch_);
 138     if (!host) {
 139       LOG(ERROR) << "Failed to launch GPU process.";
 140       FinishOnIO();
 141       return;
 142     }
 143     gpu_host_id_ = host->host_id();
 144     reused_gpu_process_ = false;
 145   } else {
 146     if (reused_gpu_process_) {
 147       // We come here if we retried to establish the channel because of a
 148       // failure in ChannelEstablishedOnIO, but we ended up with the same
 149       // process ID, meaning the failure was not because of a channel error,
 150       // but another reason. So fail now.
 151       LOG(ERROR) << "Failed to create channel.";
 152       FinishOnIO();
 153       return;
 154     }
 155     reused_gpu_process_ = true;
 156   }
 157
 158   host->EstablishGpuChannel(
 159       gpu_client_id_,
 160       true,
 161       true,
 162       base::Bind(
 163           &BrowserGpuChannelHostFactory::EstablishRequest::OnEstablishedOnIO,
 164           this));
 165 }
 166
 167 void BrowserGpuChannelHostFactory::EstablishRequest::OnEstablishedOnIO(
 168     const IPC::ChannelHandle& channel_handle,
 169     const gpu::GPUInfo& gpu_info) {
 170   if (channel_handle.name.empty() && reused_gpu_process_) {
 171     // We failed after re-using the GPU process, but it may have died in the
 172     // mean time. Retry to have a chance to create a fresh GPU process.
 173     DVLOG(1) << "Failed to create channel on existing GPU process. Trying to "
 174                 "restart GPU process.";
 175     EstablishOnIO();
 176   } else {
 177     channel_handle_ = channel_handle;
 178     gpu_info_ = gpu_info;
 179     FinishOnIO();
 180   }
 181 }
 182
 183 void BrowserGpuChannelHostFactory::EstablishRequest::FinishOnIO() {
 184   event_.Signal();
 185   main_loop_->PostTask(
 186       FROM_HERE,
 187       base::Bind(&BrowserGpuChannelHostFactory::EstablishRequest::FinishOnMain,
 188                  this));
 189 }
 190
 191 void BrowserGpuChannelHostFactory::EstablishRequest::FinishOnMain() {
 192   if (!finished_) {
 193     BrowserGpuChannelHostFactory* factory =
 194         BrowserGpuChannelHostFactory::instance();
 195     factory->GpuChannelEstablished();
 196     finished_ = true;
 197   }
 198 }
 199
 200 void BrowserGpuChannelHostFactory::EstablishRequest::Wait() {
 201   DCHECK(main_loop_->BelongsToCurrentThread());
 202   {
 203     // TODO(vadimt): Remove ScopedTracker below once crbug.com/125248 is fixed.
 204     tracked_objects::ScopedTracker tracking_profile(
 205         FROM_HERE_WITH_EXPLICIT_FUNCTION(
 206             "125248 BrowserGpuChannelHostFactory::EstablishRequest::Wait"));
 207
 208     // We're blocking the UI thread, which is generally undesirable.
 209     // In this case we need to wait for this before we can show any UI
 210     // /anyway/, so it won't cause additional jank.
 211     // TODO(piman): Make this asynchronous (http://crbug.com/125248).
 212     TRACE_EVENT0("browser",
 213                  "BrowserGpuChannelHostFactory::EstablishGpuChannelSync");
 214     base::ThreadRestrictions::ScopedAllowWait allow_wait;
 215     event_.Wait();
 216   }
 217   FinishOnMain();
 218 }
 219
 220 void BrowserGpuChannelHostFactory::EstablishRequest::Cancel() {
 221   DCHECK(main_loop_->BelongsToCurrentThread());
 222   finished_ = true;
 223 }
 224
 225 bool BrowserGpuChannelHostFactory::CanUseForTesting() {
 226   return GpuDataManager::GetInstance()->GpuAccessAllowed(NULL);
 227 }
 228
 229 void BrowserGpuChannelHostFactory::Initialize(bool establish_gpu_channel) {
 230   DCHECK(!instance_);
 231   instance_ = new BrowserGpuChannelHostFactory();
 232   if (establish_gpu_channel) {
 233     instance_->EstablishGpuChannel(CAUSE_FOR_GPU_LAUNCH_BROWSER_STARTUP,
 234                                    base::Closure());
 235   }
 236 }
 237
 238 void BrowserGpuChannelHostFactory::Terminate() {
 239   DCHECK(instance_);
 240   delete instance_;
 241   instance_ = NULL;
 242 }
 243
 244 // static
 245 void BrowserGpuChannelHostFactory::EnableGpuMemoryBufferFactoryUsage(
 246     gfx::GpuMemoryBuffer::Usage usage) {
 247   g_enabled_gpu_memory_buffer_usages.Get().insert(usage);
 248 }
 249
 250 // static
 251 bool BrowserGpuChannelHostFactory::IsGpuMemoryBufferFactoryUsageEnabled(
 252     gfx::GpuMemoryBuffer::Usage usage) {
 253   return g_enabled_gpu_memory_buffer_usages.Get().count(usage) != 0;
 254 }
 255
 256 // static
 257 uint32 BrowserGpuChannelHostFactory::GetImageTextureTarget() {
 258   if (!IsGpuMemoryBufferFactoryUsageEnabled(gfx::GpuMemoryBuffer::MAP))
 259     return GL_TEXTURE_2D;
 260
 261   std::vector<gfx::GpuMemoryBufferType> supported_types;
 262   GpuMemoryBufferFactory::GetSupportedTypes(&supported_types);
 263   DCHECK(!supported_types.empty());
 264
 265   // The GPU service will always use the preferred type.
 266   gfx::GpuMemoryBufferType type = supported_types[0];
 267
 268   switch (type) {
 269     case gfx::SURFACE_TEXTURE_BUFFER:
 270     case gfx::OZONE_NATIVE_BUFFER:
 271       // GPU memory buffers that are shared with the GL using EGLImages require
 272       // TEXTURE_EXTERNAL_OES.
 273       return GL_TEXTURE_EXTERNAL_OES;
 274     case gfx::IO_SURFACE_BUFFER:
 275       // IOSurface backed images require GL_TEXTURE_RECTANGLE_ARB.
 276       return GL_TEXTURE_RECTANGLE_ARB;
 277     default:
 278       return GL_TEXTURE_2D;
 279   }
 280 }
 281
 282 BrowserGpuChannelHostFactory::BrowserGpuChannelHostFactory()
 283     : gpu_client_id_(ChildProcessHostImpl::GenerateChildProcessUniqueId()),
 284       shutdown_event_(new base::WaitableEvent(true, false)),
 285       gpu_memory_buffer_manager_(
 286           new BrowserGpuMemoryBufferManager(this, gpu_client_id_)),
 287       gpu_host_id_(0),
 288       next_create_gpu_memory_buffer_request_id_(0) {
 289 }
 290
 291 BrowserGpuChannelHostFactory::~BrowserGpuChannelHostFactory() {
 292   DCHECK(IsMainThread());
 293   if (pending_request_.get())
 294     pending_request_->Cancel();
 295   for (size_t n = 0; n < established_callbacks_.size(); n++)
 296     established_callbacks_[n].Run();
 297   shutdown_event_->Signal();
 298 }
 299
 300 bool BrowserGpuChannelHostFactory::IsMainThread() {
 301   return BrowserThread::CurrentlyOn(BrowserThread::UI);
 302 }
 303
 304 base::MessageLoop* BrowserGpuChannelHostFactory::GetMainLoop() {
 305   return BrowserThread::UnsafeGetMessageLoopForThread(BrowserThread::UI);
 306 }
 307
 308 scoped_refptr<base::MessageLoopProxy>
 309 BrowserGpuChannelHostFactory::GetIOLoopProxy() {
 310   return BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO);
 311 }
 312
 313 scoped_ptr<base::SharedMemory>
 314 BrowserGpuChannelHostFactory::AllocateSharedMemory(size_t size) {
 315   scoped_ptr<base::SharedMemory> shm(new base::SharedMemory());
 316   if (!shm->CreateAnonymous(size))
 317     return scoped_ptr<base::SharedMemory>();
 318   return shm.Pass();
 319 }
 320
 321 void BrowserGpuChannelHostFactory::CreateViewCommandBufferOnIO(
 322     CreateRequest* request,
 323     int32 surface_id,
 324     const GPUCreateCommandBufferConfig& init_params) {
 325   GpuProcessHost* host = GpuProcessHost::FromID(gpu_host_id_);
 326   if (!host) {
 327     request->event.Signal();
 328     return;
 329   }
 330
 331   gfx::GLSurfaceHandle surface =
 332       GpuSurfaceTracker::Get()->GetSurfaceHandle(surface_id);
 333
 334   host->CreateViewCommandBuffer(
 335       surface,
 336       surface_id,
 337       gpu_client_id_,
 338       init_params,
 339       request->route_id,
 340       base::Bind(&BrowserGpuChannelHostFactory::CommandBufferCreatedOnIO,
 341                  request));
 342 }
 343
 344 // static
 345 void BrowserGpuChannelHostFactory::CommandBufferCreatedOnIO(
 346     CreateRequest* request, CreateCommandBufferResult result) {
 347   request->result = result;
 348   request->event.Signal();
 349 }
 350
 351 CreateCommandBufferResult BrowserGpuChannelHostFactory::CreateViewCommandBuffer(
 352       int32 surface_id,
 353       const GPUCreateCommandBufferConfig& init_params,
 354       int32 route_id) {
 355   CreateRequest request(route_id);
 356   GetIOLoopProxy()->PostTask(FROM_HERE, base::Bind(
 357         &BrowserGpuChannelHostFactory::CreateViewCommandBufferOnIO,
 358         base::Unretained(this),
 359         &request,
 360         surface_id,
 361         init_params));
 362   // TODO(vadimt): Remove ScopedTracker below once crbug.com/125248 is fixed.
 363   tracked_objects::ScopedTracker tracking_profile(
 364       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 365           "125248 BrowserGpuChannelHostFactory::CreateViewCommandBuffer"));
 366
 367   // We're blocking the UI thread, which is generally undesirable.
 368   // In this case we need to wait for this before we can show any UI /anyway/,
 369   // so it won't cause additional jank.
 370   // TODO(piman): Make this asynchronous (http://crbug.com/125248).
 371   TRACE_EVENT0("browser",
 372                "BrowserGpuChannelHostFactory::CreateViewCommandBuffer");
 373   base::ThreadRestrictions::ScopedAllowWait allow_wait;
 374   request.event.Wait();
 375   return request.result;
 376 }
 377
 378 // Blocking the UI thread to open a GPU channel is not supported on Android.
 379 // (Opening the initial channel to a child process involves handling a reply
 380 // task on the UI thread first, so we cannot block here.)
 381 #if !defined(OS_ANDROID)
 382 GpuChannelHost* BrowserGpuChannelHostFactory::EstablishGpuChannelSync(
 383     CauseForGpuLaunch cause_for_gpu_launch) {
 384   EstablishGpuChannel(cause_for_gpu_launch, base::Closure());
 385
 386   if (pending_request_.get())
 387     pending_request_->Wait();
 388
 389   return gpu_channel_.get();
 390 }
 391 #endif
 392
 393 void BrowserGpuChannelHostFactory::EstablishGpuChannel(
 394     CauseForGpuLaunch cause_for_gpu_launch,
 395     const base::Closure& callback) {
 396   if (gpu_channel_.get() && gpu_channel_->IsLost()) {
 397     DCHECK(!pending_request_.get());
 398     // Recreate the channel if it has been lost.
 399     gpu_channel_ = NULL;
 400   }
 401
 402   if (!gpu_channel_.get() && !pending_request_.get()) {
 403     // We should only get here if the context was lost.
 404     pending_request_ = EstablishRequest::Create(
 405         cause_for_gpu_launch, gpu_client_id_, gpu_host_id_);
 406   }
 407
 408   if (!callback.is_null()) {
 409     if (gpu_channel_.get())
 410       callback.Run();
 411     else
 412       established_callbacks_.push_back(callback);
 413   }
 414 }
 415
 416 GpuChannelHost* BrowserGpuChannelHostFactory::GetGpuChannel() {
 417   if (gpu_channel_.get() && !gpu_channel_->IsLost())
 418     return gpu_channel_.get();
 419
 420   return NULL;
 421 }
 422
 423 void BrowserGpuChannelHostFactory::GpuChannelEstablished() {
 424   DCHECK(IsMainThread());
 425   DCHECK(pending_request_.get());
 426   if (pending_request_->channel_handle().name.empty()) {
 427     DCHECK(!gpu_channel_.get());
 428   } else {
 429     // TODO(robliao): Remove ScopedTracker below once https://crbug.com/466866
 430     // is fixed.
 431     tracked_objects::ScopedTracker tracking_profile1(
 432         FROM_HERE_WITH_EXPLICIT_FUNCTION(
 433             "466866 BrowserGpuChannelHostFactory::GpuChannelEstablished1"));
 434     GetContentClient()->SetGpuInfo(pending_request_->gpu_info());
 435     gpu_channel_ =
 436         GpuChannelHost::Create(this,
 437                                pending_request_->gpu_info(),
 438                                pending_request_->channel_handle(),
 439                                shutdown_event_.get(),
 440                                BrowserGpuMemoryBufferManager::current());
 441   }
 442   gpu_host_id_ = pending_request_->gpu_host_id();
 443   pending_request_ = NULL;
 444
 445   // TODO(robliao): Remove ScopedTracker below once https://crbug.com/466866 is
 446   // fixed.
 447   tracked_objects::ScopedTracker tracking_profile2(
 448       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 449           "466866 BrowserGpuChannelHostFactory::GpuChannelEstablished2"));
 450
 451   for (size_t n = 0; n < established_callbacks_.size(); n++)
 452     established_callbacks_[n].Run();
 453
 454   established_callbacks_.clear();
 455 }
 456
 457 // static
 458 void BrowserGpuChannelHostFactory::AddFilterOnIO(
 459     int host_id,
 460     scoped_refptr<IPC::MessageFilter> filter) {
 461   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 462
 463   GpuProcessHost* host = GpuProcessHost::FromID(host_id);
 464   if (host)
 465     host->AddFilter(filter.get());
 466 }
 467
 468 bool BrowserGpuChannelHostFactory::IsGpuMemoryBufferConfigurationSupported(
 469     gfx::GpuMemoryBuffer::Format format,
 470     gfx::GpuMemoryBuffer::Usage usage) {
 471   // Return early if usage is not enabled.
 472   if (!IsGpuMemoryBufferFactoryUsageEnabled(usage))
 473     return false;
 474
 475   // Preferred type is always used by factory.
 476   std::vector<gfx::GpuMemoryBufferType> supported_types;
 477   GpuMemoryBufferFactory::GetSupportedTypes(&supported_types);
 478   DCHECK(!supported_types.empty());
 479   switch (supported_types[0]) {
 480     case gfx::SHARED_MEMORY_BUFFER:
 481       // Shared memory buffers must be created in-process.
 482       return false;
 483 #if defined(OS_MACOSX)
 484     case gfx::IO_SURFACE_BUFFER:
 485       return GpuMemoryBufferFactoryIOSurface::
 486           IsGpuMemoryBufferConfigurationSupported(format, usage);
 487 #endif
 488 #if defined(OS_ANDROID)
 489     case gfx::SURFACE_TEXTURE_BUFFER:
 490       return GpuMemoryBufferFactorySurfaceTexture::
 491           IsGpuMemoryBufferConfigurationSupported(format, usage);
 492 #endif
 493 #if defined(USE_OZONE)
 494     case gfx::OZONE_NATIVE_BUFFER:
 495       return GpuMemoryBufferFactoryOzoneNativeBuffer::
 496           IsGpuMemoryBufferConfigurationSupported(format, usage);
 497 #endif
 498     default:
 499       NOTREACHED();
 500       return false;
 501   }
 502 }
 503
 504 void BrowserGpuChannelHostFactory::CreateGpuMemoryBuffer(
 505     gfx::GpuMemoryBufferId id,
 506     const gfx::Size& size,
 507     gfx::GpuMemoryBuffer::Format format,
 508     gfx::GpuMemoryBuffer::Usage usage,
 509     int client_id,
 510     int32 surface_id,
 511     const CreateGpuMemoryBufferCallback& callback) {
 512   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 513
 514   GpuProcessHost* host = GpuProcessHost::FromID(gpu_host_id_);
 515   if (!host) {
 516     callback.Run(gfx::GpuMemoryBufferHandle());
 517     return;
 518   }
 519
 520   uint32 request_id = next_create_gpu_memory_buffer_request_id_++;
 521   create_gpu_memory_buffer_requests_[request_id] = callback;
 522
 523   host->CreateGpuMemoryBuffer(
 524       id, size, format, usage, client_id, surface_id,
 525       base::Bind(&BrowserGpuChannelHostFactory::OnGpuMemoryBufferCreated,
 526                  base::Unretained(this), request_id));
 527 }
 528
 529 void BrowserGpuChannelHostFactory::DestroyGpuMemoryBuffer(
 530     gfx::GpuMemoryBufferId id,
 531     int client_id,
 532     int32 sync_point) {
 533   BrowserThread::PostTask(
 534       BrowserThread::IO,
 535       FROM_HERE,
 536       base::Bind(&BrowserGpuChannelHostFactory::DestroyGpuMemoryBufferOnIO,
 537                  base::Unretained(this),
 538                  id,
 539                  client_id,
 540                  sync_point));
 541 }
 542
 543 void BrowserGpuChannelHostFactory::DestroyGpuMemoryBufferOnIO(
 544     gfx::GpuMemoryBufferId id,
 545     int client_id,
 546     int32 sync_point) {
 547   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 548
 549   GpuProcessHost* host = GpuProcessHost::FromID(gpu_host_id_);
 550   if (!host)
 551     return;
 552
 553   host->DestroyGpuMemoryBuffer(id, client_id, sync_point);
 554 }
 555
 556 void BrowserGpuChannelHostFactory::OnGpuMemoryBufferCreated(
 557     uint32 request_id,
 558     const gfx::GpuMemoryBufferHandle& handle) {
 559   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 560
 561   CreateGpuMemoryBufferCallbackMap::iterator iter =
 562       create_gpu_memory_buffer_requests_.find(request_id);
 563   DCHECK(iter != create_gpu_memory_buffer_requests_.end());
 564   iter->second.Run(handle);
 565   create_gpu_memory_buffer_requests_.erase(iter);
 566 }
 567
 568 }  // namespace content