Use gpu::Mailbox instead of std:string in IPCs

- easier to read
- safer since gpu::Mailbox is constant size and checked in the ParamTraits

BUG=None

Review URL: https://codereview.chromium.org/148003006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251207 0039d316-1c4b-4281-b951-d872f2087c98

19 files changed, 63 insertions, 80 deletions

diff --git a/content/browser/browser_plugin/browser_plugin_guest.cc b/content/browser/browser_plugin/browser_plugin_guest.cc
index 9e8e517..68db4d9 100644
--- a/content/browser/browser_plugin/browser_plugin_guest.cc
+++ b/content/browser/browser_plugin/browser_plugin_guest.cc
@@ -1157,10 +1157,10 @@ void BrowserPluginGuest::RenderProcessGone(base::TerminationStatus status) {
 void BrowserPluginGuest::AcknowledgeBufferPresent(
     int route_id,
     int gpu_host_id,
-    const std::string& mailbox_name,
+    const gpu::Mailbox& mailbox,
     uint32 sync_point) {
   AcceleratedSurfaceMsg_BufferPresented_Params ack_params;
-  ack_params.mailbox_name = mailbox_name;
+  ack_params.mailbox = mailbox;
   ack_params.sync_point = sync_point;
   RenderWidgetHostImpl::AcknowledgeBufferPresent(route_id,
                                                  gpu_host_id,
@@ -1610,7 +1610,7 @@ void BrowserPluginGuest::OnSwapBuffersACK(
     int instance_id,
     const FrameHostMsg_BuffersSwappedACK_Params& params) {
   AcknowledgeBufferPresent(params.gpu_route_id, params.gpu_host_id,
-                           params.mailbox_name, params.sync_point);
+                           params.mailbox, params.sync_point);
 
 // This is only relevant on MACOSX and WIN when threaded compositing
 // is not enabled. In threaded mode, above ACK is sufficient.
diff --git a/content/browser/browser_plugin/browser_plugin_guest.h b/content/browser/browser_plugin/browser_plugin_guest.h
index a986bdb..870783c 100644
--- a/content/browser/browser_plugin/browser_plugin_guest.h
+++ b/content/browser/browser_plugin/browser_plugin_guest.h
@@ -67,6 +67,10 @@ namespace gfx {
 class Range;
 }
 
+namespace gpu {
+struct Mailbox;
+}
+
 namespace content {
 
 class BrowserPluginHostFactory;
@@ -286,7 +290,7 @@ class CONTENT_EXPORT BrowserPluginGuest
   // BrowserPluginGuest is already destroyed.
   static void AcknowledgeBufferPresent(int route_id,
                                        int gpu_host_id,
-                                       const std::string& mailbox_name,
+                                       const gpu::Mailbox& mailbox,
                                        uint32 sync_point);
 
   // Returns whether BrowserPluginGuest is interested in receiving the given
diff --git a/content/browser/browser_plugin/browser_plugin_guest_manager.cc b/content/browser/browser_plugin/browser_plugin_guest_manager.cc
index 405a233..4ef9e29 100644
--- a/content/browser/browser_plugin/browser_plugin_guest_manager.cc
+++ b/content/browser/browser_plugin/browser_plugin_guest_manager.cc
@@ -221,7 +221,7 @@ void BrowserPluginGuestManager::OnUnhandledSwapBuffersACK(
     const FrameHostMsg_BuffersSwappedACK_Params& params) {
   BrowserPluginGuest::AcknowledgeBufferPresent(params.gpu_route_id,
                                                params.gpu_host_id,
-                                               params.mailbox_name,
+                                               params.mailbox,
                                                params.sync_point);
 }
 
diff --git a/content/browser/compositor/gpu_process_transport_factory.cc b/content/browser/compositor/gpu_process_transport_factory.cc
index d72958b..6724060 100644
--- a/content/browser/compositor/gpu_process_transport_factory.cc
+++ b/content/browser/compositor/gpu_process_transport_factory.cc
@@ -29,6 +29,7 @@
 #include "content/common/gpu/gpu_process_launch_causes.h"
 #include "gpu/GLES2/gl2extchromium.h"
 #include "gpu/command_buffer/client/gles2_interface.h"
+#include "gpu/command_buffer/common/mailbox.h"
 #include "third_party/khronos/GLES2/gl2.h"
 #include "ui/compositor/compositor.h"
 #include "ui/compositor/compositor_constants.h"
@@ -113,29 +114,27 @@ class ImageTransportClientTexture : public OwnedTexture {
                      device_scale_factor,
                      texture_id) {}
 
-  virtual void Consume(const std::string& mailbox_name,
+  virtual void Consume(const gpu::Mailbox& mailbox,
                        const gfx::Size& new_size) OVERRIDE {
-    DCHECK(mailbox_name.size() == GL_MAILBOX_SIZE_CHROMIUM);
-    mailbox_name_ = mailbox_name;
-    if (mailbox_name.empty())
+    mailbox_ = mailbox;
+    if (mailbox.IsZero())
       return;
 
     DCHECK(provider_ && texture_id_);
     GLES2Interface* gl = provider_->ContextGL();
     gl->BindTexture(GL_TEXTURE_2D, texture_id_);
-    gl->ConsumeTextureCHROMIUM(
-        GL_TEXTURE_2D, reinterpret_cast<const GLbyte*>(mailbox_name.c_str()));
+    gl->ConsumeTextureCHROMIUM(GL_TEXTURE_2D, mailbox.name);
     size_ = new_size;
     gl->ShallowFlushCHROMIUM();
   }
 
-  virtual std::string Produce() OVERRIDE { return mailbox_name_; }
+  virtual gpu::Mailbox Produce() OVERRIDE { return mailbox_; }
 
  protected:
   virtual ~ImageTransportClientTexture() {}
 
  private:
-  std::string mailbox_name_;
+  gpu::Mailbox mailbox_;
   DISALLOW_COPY_AND_ASSIGN(ImageTransportClientTexture);
 };
 
diff --git a/content/browser/compositor/no_transport_image_transport_factory.cc b/content/browser/compositor/no_transport_image_transport_factory.cc
index f278e49..d67be0c 100644
--- a/content/browser/compositor/no_transport_image_transport_factory.cc
+++ b/content/browser/compositor/no_transport_image_transport_factory.cc
@@ -25,7 +25,7 @@ class FakeTexture : public ui::Texture {
 
   virtual unsigned int PrepareTexture() OVERRIDE { return texture_; }
 
-  virtual void Consume(const std::string& mailbox_name,
+  virtual void Consume(const gpu::Mailbox& mailbox,
                        const gfx::Size& new_size) OVERRIDE {
     size_ = new_size;
   }
diff --git a/content/browser/frame_host/cross_process_frame_connector.cc b/content/browser/frame_host/cross_process_frame_connector.cc
index f386df8..0378181 100644
--- a/content/browser/frame_host/cross_process_frame_connector.cc
+++ b/content/browser/frame_host/cross_process_frame_connector.cc
@@ -67,7 +67,7 @@ void CrossProcessFrameConnector::ChildFrameBuffersSwapped(
 
   FrameMsg_BuffersSwapped_Params params;
   params.size = gpu_params.size;
-  params.mailbox_name = gpu_params.mailbox_name;
+  params.mailbox = gpu_params.mailbox;
   params.gpu_route_id = gpu_params.route_id;
   params.gpu_host_id = gpu_host_id;
 
@@ -94,7 +94,7 @@ void CrossProcessFrameConnector::ChildFrameCompositorFrameSwapped(
 void CrossProcessFrameConnector::OnBuffersSwappedACK(
     const FrameHostMsg_BuffersSwappedACK_Params& params) {
   AcceleratedSurfaceMsg_BufferPresented_Params ack_params;
-  ack_params.mailbox_name = params.mailbox_name;
+  ack_params.mailbox = params.mailbox;
   ack_params.sync_point = params.sync_point;
   RenderWidgetHostImpl::AcknowledgeBufferPresent(params.gpu_route_id,
                                                  params.gpu_host_id,
diff --git a/content/browser/frame_host/render_widget_host_view_guest.cc b/content/browser/frame_host/render_widget_host_view_guest.cc
index 0e26c92..eef781b 100644
--- a/content/browser/frame_host/render_widget_host_view_guest.cc
+++ b/content/browser/frame_host/render_widget_host_view_guest.cc
@@ -170,7 +170,7 @@ void RenderWidgetHostViewGuest::AcceleratedSurfaceBuffersSwapped(
   guest_->clear_damage_buffer();
   FrameMsg_BuffersSwapped_Params guest_params;
   guest_params.size = params.size;
-  guest_params.mailbox_name = params.mailbox_name;
+  guest_params.mailbox = params.mailbox;
   guest_params.gpu_route_id = params.route_id;
   guest_params.gpu_host_id = gpu_host_id;
   guest_->SendMessageToEmbedder(
diff --git a/content/browser/gpu/gpu_process_host_ui_shim.cc b/content/browser/gpu/gpu_process_host_ui_shim.cc
index 4d46484..ec62dff 100644
--- a/content/browser/gpu/gpu_process_host_ui_shim.cc
+++ b/content/browser/gpu/gpu_process_host_ui_shim.cc
@@ -288,17 +288,13 @@ void GpuProcessHostUIShim::OnAcceleratedSurfaceBuffersSwapped(
                                "GpuHostMsg_AcceleratedSurfaceBuffersSwapped"))
     return;
   AcceleratedSurfaceMsg_BufferPresented_Params ack_params;
-  ack_params.mailbox_name = params.mailbox_name;
+  ack_params.mailbox = params.mailbox;
   ack_params.sync_point = 0;
   ScopedSendOnIOThread delayed_send(
       host_id_,
       new AcceleratedSurfaceMsg_BufferPresented(params.route_id,
                                                 ack_params));
 
-  if (!params.mailbox_name.empty() &&
-      params.mailbox_name.length() != GL_MAILBOX_SIZE_CHROMIUM)
-    return;
-
   RenderWidgetHostViewPort* view = GetRenderWidgetHostViewFromSurfaceID(
       params.surface_id);
   if (!view)
@@ -338,17 +334,13 @@ void GpuProcessHostUIShim::OnAcceleratedSurfacePostSubBuffer(
                                "GpuHostMsg_AcceleratedSurfacePostSubBuffer"))
     return;
   AcceleratedSurfaceMsg_BufferPresented_Params ack_params;
-  ack_params.mailbox_name = params.mailbox_name;
+  ack_params.mailbox = params.mailbox;
   ack_params.sync_point = 0;
   ScopedSendOnIOThread delayed_send(
       host_id_,
       new AcceleratedSurfaceMsg_BufferPresented(params.route_id,
                                                 ack_params));
 
-  if (!params.mailbox_name.empty() &&
-      params.mailbox_name.length() != GL_MAILBOX_SIZE_CHROMIUM)
-    return;
-
   RenderWidgetHostViewPort* view =
       GetRenderWidgetHostViewFromSurfaceID(params.surface_id);
   if (!view)
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.cc b/content/browser/renderer_host/render_widget_host_view_aura.cc
index 81245e5..2a926bc 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.cc
+++ b/content/browser/renderer_host/render_widget_host_view_aura.cc
@@ -327,10 +327,7 @@ void SendCompositorFrameAck(
   DCHECK(!texture_to_produce.get() || !skip_frame);
   if (texture_to_produce.get()) {
     GLHelper* gl_helper = ImageTransportFactory::GetInstance()->GetGLHelper();
-    std::string mailbox_name = texture_to_produce->Produce();
-    std::copy(mailbox_name.data(),
-              mailbox_name.data() + mailbox_name.length(),
-              reinterpret_cast<char*>(ack.gl_frame_data->mailbox.name));
+    ack.gl_frame_data->mailbox = texture_to_produce->Produce();
     ack.gl_frame_data->size = texture_to_produce->size();
     ack.gl_frame_data->sync_point =
         gl_helper ? gl_helper->InsertSyncPoint() : 0;
@@ -348,7 +345,7 @@ void SendCompositorFrameAck(
 void AcknowledgeBufferForGpu(
     int32 route_id,
     int gpu_host_id,
-    const std::string& received_mailbox,
+    const gpu::Mailbox& received_mailbox,
     bool skip_frame,
     const scoped_refptr<ui::Texture>& texture_to_produce) {
   AcceleratedSurfaceMsg_BufferPresented_Params ack;
@@ -356,10 +353,10 @@ void AcknowledgeBufferForGpu(
   DCHECK(!texture_to_produce.get() || !skip_frame);
   if (texture_to_produce.get()) {
     GLHelper* gl_helper = ImageTransportFactory::GetInstance()->GetGLHelper();
-    ack.mailbox_name = texture_to_produce->Produce();
+    ack.mailbox = texture_to_produce->Produce();
     sync_point = gl_helper ? gl_helper->InsertSyncPoint() : 0;
   } else if (skip_frame) {
-    ack.mailbox_name = received_mailbox;
+    ack.mailbox = received_mailbox;
     ack.sync_point = 0;
   }
 
@@ -1302,7 +1299,7 @@ bool RenderWidgetHostViewAura::SwapBuffersPrepare(
     const gfx::Rect& surface_rect,
     float surface_scale_factor,
     const gfx::Rect& damage_rect,
-    const std::string& mailbox_name,
+    const gpu::Mailbox& mailbox,
     const BufferPresentedCallback& ack_callback) {
   if (last_swapped_surface_size_ != surface_rect.size()) {
     // The surface could have shrunk since we skipped an update, in which
@@ -1315,7 +1312,7 @@ bool RenderWidgetHostViewAura::SwapBuffersPrepare(
 
   if (ShouldSkipFrame(ConvertSizeToDIP(surface_scale_factor,
                                        surface_rect.size())) ||
-      mailbox_name.empty()) {
+      mailbox.IsZero()) {
     skipped_damage_.op(RectToSkIRect(damage_rect), SkRegion::kUnion_Op);
     ack_callback.Run(true, scoped_refptr<ui::Texture>());
     return false;
@@ -1330,7 +1327,7 @@ bool RenderWidgetHostViewAura::SwapBuffersPrepare(
     return false;
   }
 
-  current_surface_->Consume(mailbox_name, surface_rect.size());
+  current_surface_->Consume(mailbox, surface_rect.size());
   released_front_lock_ = NULL;
   UpdateExternalTexture();
 
@@ -1396,11 +1393,11 @@ void RenderWidgetHostViewAura::AcceleratedSurfaceBuffersSwapped(
       &AcknowledgeBufferForGpu,
       params_in_pixel.route_id,
       gpu_host_id,
-      params_in_pixel.mailbox_name);
+      params_in_pixel.mailbox);
   BuffersSwapped(params_in_pixel.size,
                  gfx::Rect(params_in_pixel.size),
                  params_in_pixel.scale_factor,
-                 params_in_pixel.mailbox_name,
+                 params_in_pixel.mailbox,
                  params_in_pixel.latency_info,
                  ack_callback);
 }
@@ -1691,13 +1688,10 @@ void RenderWidgetHostViewAura::OnSwapCompositorFrame(
   GLHelper* gl_helper = ImageTransportFactory::GetInstance()->GetGLHelper();
   gl_helper->WaitSyncPoint(frame->gl_frame_data->sync_point);
 
-  std::string mailbox_name(
-      reinterpret_cast<const char*>(frame->gl_frame_data->mailbox.name),
-      sizeof(frame->gl_frame_data->mailbox.name));
   BuffersSwapped(frame->gl_frame_data->size,
                  frame->gl_frame_data->sub_buffer_rect,
                  frame->metadata.device_scale_factor,
-                 mailbox_name,
+                 frame->gl_frame_data->mailbox,
                  frame->metadata.latency_info,
                  ack_callback);
 }
@@ -1725,7 +1719,7 @@ void RenderWidgetHostViewAura::BuffersSwapped(
     const gfx::Size& surface_size,
     const gfx::Rect& damage_rect,
     float surface_scale_factor,
-    const std::string& mailbox_name,
+    const gpu::Mailbox& mailbox,
     const std::vector<ui::LatencyInfo>& latency_info,
     const BufferPresentedCallback& ack_callback) {
   scoped_refptr<ui::Texture> previous_texture(current_surface_);
@@ -1735,7 +1729,7 @@ void RenderWidgetHostViewAura::BuffersSwapped(
   if (!SwapBuffersPrepare(surface_rect,
                           surface_scale_factor,
                           damage_rect,
-                          mailbox_name,
+                          mailbox,
                           ack_callback)) {
     return;
   }
@@ -1802,11 +1796,11 @@ void RenderWidgetHostViewAura::AcceleratedSurfacePostSubBuffer(
       base::Bind(&AcknowledgeBufferForGpu,
                  params_in_pixel.route_id,
                  gpu_host_id,
-                 params_in_pixel.mailbox_name);
+                 params_in_pixel.mailbox);
   BuffersSwapped(params_in_pixel.surface_size,
                  damage_rect,
                  params_in_pixel.surface_scale_factor,
-                 params_in_pixel.mailbox_name,
+                 params_in_pixel.mailbox,
                  params_in_pixel.latency_info,
                  ack_callback);
 }
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.h b/content/browser/renderer_host/render_widget_host_view_aura.h
index 3c3757d..0e01067 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.h
+++ b/content/browser/renderer_host/render_widget_host_view_aura.h
@@ -60,6 +60,10 @@ class Canvas;
 class Display;
 }
 
+namespace gpu {
+struct Mailbox;
+}
+
 namespace ui {
 class CompositorLock;
 class CompositorVSyncManager;
@@ -530,14 +534,14 @@ class CONTENT_EXPORT RenderWidgetHostViewAura
   void BuffersSwapped(const gfx::Size& surface_size,
                       const gfx::Rect& damage_rect,
                       float surface_scale_factor,
-                      const std::string& mailbox_name,
+                      const gpu::Mailbox& mailbox,
                       const std::vector<ui::LatencyInfo>& latency_info,
                       const BufferPresentedCallback& ack_callback);
 
   bool SwapBuffersPrepare(const gfx::Rect& surface_rect,
                           float surface_scale_factor,
                           const gfx::Rect& damage_rect,
-                          const std::string& mailbox_name,
+                          const gpu::Mailbox& mailbox,
                           const BufferPresentedCallback& ack_callback);
 
   void SwapBuffersCompleted(
diff --git a/content/browser/renderer_host/render_widget_host_view_aura_unittest.cc b/content/browser/renderer_host/render_widget_host_view_aura_unittest.cc
index 6911f28..cd5cb3f 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura_unittest.cc
+++ b/content/browser/renderer_host/render_widget_host_view_aura_unittest.cc
@@ -949,7 +949,7 @@ TEST_F(RenderWidgetHostViewAuraTest, SwapNotifiesWindow) {
   GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params params;
   params.surface_id = widget_host_->surface_id();
   params.route_id = widget_host_->GetRoutingID();
-  params.mailbox_name = std::string(64, '1');
+  memset(params.mailbox.name, '1', sizeof(params.mailbox.name));
   params.size = view_size;
   params.scale_factor = 1.f;
 
@@ -968,7 +968,7 @@ TEST_F(RenderWidgetHostViewAuraTest, SwapNotifiesWindow) {
   GpuHostMsg_AcceleratedSurfacePostSubBuffer_Params post_params;
   post_params.surface_id = widget_host_->surface_id();
   post_params.route_id = widget_host_->GetRoutingID();
-  post_params.mailbox_name = std::string(64, '1');
+  memset(post_params.mailbox.name, '1', sizeof(post_params.mailbox.name));
   post_params.surface_size = gfx::Size(200, 200);
   post_params.surface_scale_factor = 2.f;
   post_params.x = 40;
diff --git a/content/common/frame_param_macros.h b/content/common/frame_param_macros.h
index 2cd44e7..3f37975 100644
--- a/content/common/frame_param_macros.h
+++ b/content/common/frame_param_macros.h
@@ -24,7 +24,7 @@
 IPC_STRUCT_BEGIN(FrameMsg_BuffersSwapped_Params)
   IPC_STRUCT_MEMBER(int, gpu_host_id)
   IPC_STRUCT_MEMBER(int, gpu_route_id)
-  IPC_STRUCT_MEMBER(std::string, mailbox_name)
+  IPC_STRUCT_MEMBER(gpu::Mailbox, mailbox)
   IPC_STRUCT_MEMBER(gfx::Size, size)
 IPC_STRUCT_END()
 
@@ -40,7 +40,7 @@ IPC_STRUCT_END()
 IPC_STRUCT_BEGIN(FrameHostMsg_BuffersSwappedACK_Params)
   IPC_STRUCT_MEMBER(int, gpu_host_id)
   IPC_STRUCT_MEMBER(int, gpu_route_id)
-  IPC_STRUCT_MEMBER(std::string, mailbox_name)
+  IPC_STRUCT_MEMBER(gpu::Mailbox, mailbox)
   IPC_STRUCT_MEMBER(uint32, sync_point)
 IPC_STRUCT_END()
 
diff --git a/content/common/gpu/gpu_messages.h b/content/common/gpu/gpu_messages.h
index 7754ec3..2db1a1d 100644
--- a/content/common/gpu/gpu_messages.h
+++ b/content/common/gpu/gpu_messages.h
@@ -70,7 +70,7 @@ IPC_STRUCT_BEGIN(GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params)
   IPC_STRUCT_MEMBER(int32, surface_id)
   IPC_STRUCT_MEMBER(uint64, surface_handle)
   IPC_STRUCT_MEMBER(int32, route_id)
-  IPC_STRUCT_MEMBER(std::string, mailbox_name)
+  IPC_STRUCT_MEMBER(gpu::Mailbox, mailbox)
   IPC_STRUCT_MEMBER(gfx::Size, size)
   IPC_STRUCT_MEMBER(float, scale_factor)
   IPC_STRUCT_MEMBER(std::vector<ui::LatencyInfo>, latency_info)
@@ -84,7 +84,7 @@ IPC_STRUCT_BEGIN(GpuHostMsg_AcceleratedSurfacePostSubBuffer_Params)
   IPC_STRUCT_MEMBER(int, y)
   IPC_STRUCT_MEMBER(int, width)
   IPC_STRUCT_MEMBER(int, height)
-  IPC_STRUCT_MEMBER(std::string, mailbox_name)
+  IPC_STRUCT_MEMBER(gpu::Mailbox, mailbox)
   IPC_STRUCT_MEMBER(gfx::Size, surface_size)
   IPC_STRUCT_MEMBER(float, surface_scale_factor)
   IPC_STRUCT_MEMBER(std::vector<ui::LatencyInfo>, latency_info)
@@ -95,7 +95,7 @@ IPC_STRUCT_BEGIN(GpuHostMsg_AcceleratedSurfaceRelease_Params)
 IPC_STRUCT_END()
 
 IPC_STRUCT_BEGIN(AcceleratedSurfaceMsg_BufferPresented_Params)
-  IPC_STRUCT_MEMBER(std::string, mailbox_name)
+  IPC_STRUCT_MEMBER(gpu::Mailbox, mailbox)
   IPC_STRUCT_MEMBER(uint32, sync_point)
 #if defined(OS_MACOSX)
   IPC_STRUCT_MEMBER(int32, renderer_id)
diff --git a/content/common/gpu/texture_image_transport_surface.cc b/content/common/gpu/texture_image_transport_surface.cc
index f13a986..30a54fb 100644
--- a/content/common/gpu/texture_image_transport_surface.cc
+++ b/content/common/gpu/texture_image_transport_surface.cc
@@ -218,9 +218,7 @@ bool TextureImageTransportSurface::SwapBuffers() {
   GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params params;
   params.size = backbuffer_size();
   params.scale_factor = scale_factor_;
-  params.mailbox_name.assign(
-      reinterpret_cast<const char*>(&back_mailbox_),
-      sizeof(back_mailbox_));
+  params.mailbox = back_mailbox_;
 
   glFlush();
 
@@ -258,9 +256,7 @@ bool TextureImageTransportSurface::PostSubBuffer(
   params.y = y;
   params.width = width;
   params.height = height;
-  params.mailbox_name.assign(
-      reinterpret_cast<const char*>(&back_mailbox_),
-      sizeof(back_mailbox_));
+  params.mailbox = back_mailbox_;
 
   glFlush();
 
@@ -294,18 +290,17 @@ unsigned TextureImageTransportSurface::GetFormat() {
 void TextureImageTransportSurface::OnBufferPresented(
     const AcceleratedSurfaceMsg_BufferPresented_Params& params) {
   if (params.sync_point == 0) {
-    BufferPresentedImpl(params.mailbox_name);
+    BufferPresentedImpl(params.mailbox);
   } else {
     helper_->manager()->sync_point_manager()->AddSyncPointCallback(
         params.sync_point,
         base::Bind(&TextureImageTransportSurface::BufferPresentedImpl,
                    this,
-                   params.mailbox_name));
+                   params.mailbox));
   }
 }
 
-void TextureImageTransportSurface::BufferPresentedImpl(
-    const std::string& mailbox_name) {
+void TextureImageTransportSurface::BufferPresentedImpl(const Mailbox& mailbox) {
   DCHECK(is_swap_buffers_pending_);
   is_swap_buffers_pending_ = false;
 
@@ -321,11 +316,8 @@ void TextureImageTransportSurface::BufferPresentedImpl(
   DCHECK(backbuffer_.get());
 
   bool swap = true;
-  if (!mailbox_name.empty()) {
-    DCHECK(mailbox_name.length() == GL_MAILBOX_SIZE_CHROMIUM);
-    if (!memcmp(mailbox_name.data(),
-                &back_mailbox_,
-                mailbox_name.length())) {
+  if (!mailbox.IsZero()) {
+    if (mailbox != back_mailbox_) {
       // The browser has skipped the frame to unblock the GPU process, waiting
       // for one of the right size, and returned the back buffer, so don't swap.
       swap = false;
diff --git a/content/common/gpu/texture_image_transport_surface.h b/content/common/gpu/texture_image_transport_surface.h
index ab3eb44..a86ff27 100644
--- a/content/common/gpu/texture_image_transport_surface.h
+++ b/content/common/gpu/texture_image_transport_surface.h
@@ -74,7 +74,7 @@ class TextureImageTransportSurface
   void AttachBackTextureToFBO();
   void ReleaseBackTexture();
   void ReleaseFrontTexture();
-  void BufferPresentedImpl(const std::string& mailbox_name);
+  void BufferPresentedImpl(const gpu::Mailbox& mailbox_name);
 
   // The framebuffer that represents this surface (service id). Allocated lazily
   // in OnMakeCurrent.
diff --git a/content/renderer/browser_plugin/browser_plugin.cc b/content/renderer/browser_plugin/browser_plugin.cc
index 974c3b0..3d20a6e 100644
--- a/content/renderer/browser_plugin/browser_plugin.cc
+++ b/content/renderer/browser_plugin/browser_plugin.cc
@@ -437,7 +437,7 @@ void BrowserPlugin::OnBuffersSwapped(
   EnableCompositing(true);
 
   compositing_helper_->OnBuffersSwapped(params.size,
-                                        params.mailbox_name,
+                                        params.mailbox,
                                         params.gpu_route_id,
                                         params.gpu_host_id,
                                         GetDeviceScaleFactor());
diff --git a/content/renderer/child_frame_compositing_helper.cc b/content/renderer/child_frame_compositing_helper.cc
index 15cf383..cc3bc50 100644
--- a/content/renderer/child_frame_compositing_helper.cc
+++ b/content/renderer/child_frame_compositing_helper.cc
@@ -246,12 +246,10 @@ void ChildFrameCompositingHelper::MailboxReleased(SwapBuffersInfo mailbox,
   ack_pending_ = false;
   switch (mailbox.type) {
     case TEXTURE_IMAGE_TRANSPORT: {
-      std::string mailbox_name(reinterpret_cast<const char*>(mailbox.name.name),
-                               sizeof(mailbox.name.name));
       FrameHostMsg_BuffersSwappedACK_Params params;
       params.gpu_host_id = mailbox.host_id;
       params.gpu_route_id = mailbox.route_id;
-      params.mailbox_name = mailbox_name;
+      params.mailbox = mailbox.name;
       params.sync_point = sync_point;
       SendBuffersSwappedACKToBrowser(params);
       break;
@@ -378,12 +376,12 @@ void ChildFrameCompositingHelper::OnBuffersSwappedPrivate(
 
 void ChildFrameCompositingHelper::OnBuffersSwapped(
     const gfx::Size& size,
-    const std::string& mailbox_name,
+    const gpu::Mailbox& mailbox,
     int gpu_route_id,
     int gpu_host_id,
     float device_scale_factor) {
   SwapBuffersInfo swap_info;
-  swap_info.name.SetName(reinterpret_cast<const int8*>(mailbox_name.data()));
+  swap_info.name = mailbox;
   swap_info.type = TEXTURE_IMAGE_TRANSPORT;
   swap_info.size = size;
   swap_info.route_id = gpu_route_id;
diff --git a/content/renderer/child_frame_compositing_helper.h b/content/renderer/child_frame_compositing_helper.h
index 686d9a2..1ec0585 100644
--- a/content/renderer/child_frame_compositing_helper.h
+++ b/content/renderer/child_frame_compositing_helper.h
@@ -69,7 +69,7 @@ class CONTENT_EXPORT ChildFrameCompositingHelper
   void EnableCompositing(bool);
   void OnContainerDestroy();
   void OnBuffersSwapped(const gfx::Size& size,
-                        const std::string& mailbox_name,
+                        const gpu::Mailbox& mailbox,
                         int gpu_route_id,
                         int gpu_host_id,
                         float device_scale_factor);
diff --git a/content/renderer/render_frame_impl.cc b/content/renderer/render_frame_impl.cc
index 1b13f68..af5e0d5 100644
--- a/content/renderer/render_frame_impl.cc
+++ b/content/renderer/render_frame_impl.cc
@@ -487,7 +487,7 @@ void RenderFrameImpl::OnBuffersSwapped(
   }
   compositing_helper_->OnBuffersSwapped(
       params.size,
-      params.mailbox_name,
+      params.mailbox,
       params.gpu_route_id,
       params.gpu_host_id,
       render_view_->GetWebView()->deviceScaleFactor());