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

gpu::Mailbox is safer since the size is checked in the deserializer. It's also
overall less code.

BUG=None


Review URL: https://chromiumcodereview.appspot.com/12440005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@186627 0039d316-1c4b-4281-b951-d872f2087c98

28 files changed, 115 insertions, 128 deletions

diff --git a/cc/texture_layer_unittest.cc b/cc/texture_layer_unittest.cc
index 6aaf459..7ebdac6 100644
--- a/cc/texture_layer_unittest.cc
+++ b/cc/texture_layer_unittest.cc
@@ -293,8 +293,10 @@ public:
     }
 
     void setMailbox(char mailbox_char) {
+        gpu::Mailbox name;
+        memset(name.name, mailbox_char, sizeof(name.name));
         TextureMailbox mailbox(
-            std::string(64, mailbox_char),
+            name,
             base::Bind(
                 &TextureLayerImplWithMailboxThreadedCallback::releaseCallback,
                 base::Unretained(this)));
diff --git a/cc/texture_mailbox.cc b/cc/texture_mailbox.cc
index b534605..437fb1c 100644
--- a/cc/texture_mailbox.cc
+++ b/cc/texture_mailbox.cc
@@ -12,18 +12,6 @@ TextureMailbox::TextureMailbox()
 }
 
 TextureMailbox::TextureMailbox(
-    const std::string& mailbox_name,
-    const ReleaseCallback& mailbox_callback)
-    : callback_(mailbox_callback),
-      sync_point_(0) {
-  DCHECK(mailbox_name.empty() == mailbox_callback.is_null());
-  if (!mailbox_name.empty()) {
-    CHECK(mailbox_name.size() == sizeof(name_.name));
-    name_.SetName(reinterpret_cast<const int8*>(mailbox_name.data()));
-  }
-}
-
-TextureMailbox::TextureMailbox(
     const gpu::Mailbox& mailbox_name,
     const ReleaseCallback& mailbox_callback)
     : callback_(mailbox_callback),
diff --git a/cc/texture_mailbox.h b/cc/texture_mailbox.h
index 9314ddd..7520087 100644
--- a/cc/texture_mailbox.h
+++ b/cc/texture_mailbox.h
@@ -18,8 +18,6 @@ class CC_EXPORT TextureMailbox {
  public:
   typedef base::Callback<void(unsigned)> ReleaseCallback;
   TextureMailbox();
-  TextureMailbox(const std::string& mailbox_name,
-                 const ReleaseCallback& callback);
   TextureMailbox(const gpu::Mailbox& mailbox_name,
                  const ReleaseCallback& callback);
   TextureMailbox(const gpu::Mailbox& mailbox_name,
diff --git a/content/browser/browser_plugin/browser_plugin_guest.cc b/content/browser/browser_plugin/browser_plugin_guest.cc
index da41a34..a649a5f 100644
--- a/content/browser/browser_plugin/browser_plugin_guest.cc
+++ b/content/browser/browser_plugin/browser_plugin_guest.cc
@@ -445,7 +445,7 @@ void BrowserPluginGuest::RenderViewGone(base::TerminationStatus status) {
 void BrowserPluginGuest::AcknowledgeBufferPresent(
     int route_id,
     int gpu_host_id,
-    const std::string& mailbox_name,
+    const gpu::Mailbox& mailbox_name,
     uint32 sync_point) {
   AcceleratedSurfaceMsg_BufferPresented_Params ack_params;
   ack_params.mailbox_name = mailbox_name;
@@ -728,7 +728,7 @@ void BrowserPluginGuest::OnRespondPermission(
 void BrowserPluginGuest::OnSwapBuffersACK(int instance_id,
                                           int route_id,
                                           int gpu_host_id,
-                                          const std::string& mailbox_name,
+                                          const gpu::Mailbox& mailbox_name,
                                           uint32 sync_point) {
   AcknowledgeBufferPresent(route_id, gpu_host_id, mailbox_name, sync_point);
 
diff --git a/content/browser/browser_plugin/browser_plugin_guest.h b/content/browser/browser_plugin/browser_plugin_guest.h
index 1a31551..73ecae6 100644
--- a/content/browser/browser_plugin/browser_plugin_guest.h
+++ b/content/browser/browser_plugin/browser_plugin_guest.h
@@ -50,6 +50,10 @@ struct ViewHostMsg_UpdateRect_Params;
 class WebCursor;
 struct WebDropData;
 
+namespace gpu {
+struct Mailbox;
+}
+
 namespace WebKit {
 class WebInputEvent;
 }
@@ -181,7 +185,7 @@ class CONTENT_EXPORT BrowserPluginGuest : public NotificationObserver,
   // BrowserPluginGuest is already destroyed.
   static void AcknowledgeBufferPresent(int route_id,
                                        int gpu_host_id,
-                                       const std::string& mailbox_name,
+                                       const gpu::Mailbox& mailbox_name,
                                        uint32 sync_point);
 
   // Returns whether BrowserPluginGuest is interested in receiving the given
@@ -292,7 +296,7 @@ class CONTENT_EXPORT BrowserPluginGuest : public NotificationObserver,
   void OnSwapBuffersACK(int instance_id,
                         int route_id,
                         int gpu_host_id,
-                        const std::string& mailbox_name,
+                        const gpu::Mailbox& mailbox_name,
                         uint32 sync_point);
 
   void OnTerminateGuest(int instance_id);
diff --git a/content/browser/browser_plugin/browser_plugin_guest_manager.cc b/content/browser/browser_plugin/browser_plugin_guest_manager.cc
index a96dcfc..fc38cc7 100644
--- a/content/browser/browser_plugin/browser_plugin_guest_manager.cc
+++ b/content/browser/browser_plugin/browser_plugin_guest_manager.cc
@@ -211,7 +211,7 @@ void BrowserPluginGuestManager::OnUnhandledSwapBuffersACK(
     int instance_id,
     int route_id,
     int gpu_host_id,
-    const std::string& mailbox_name,
+    const gpu::Mailbox& mailbox_name,
     uint32 sync_point) {
   BrowserPluginGuest::AcknowledgeBufferPresent(route_id,
                                                gpu_host_id,
diff --git a/content/browser/browser_plugin/browser_plugin_guest_manager.h b/content/browser/browser_plugin/browser_plugin_guest_manager.h
index a41dfc4..6362af3 100644
--- a/content/browser/browser_plugin/browser_plugin_guest_manager.h
+++ b/content/browser/browser_plugin/browser_plugin_guest_manager.h
@@ -22,6 +22,10 @@ namespace gfx {
 class Point;
 }
 
+namespace gpu {
+struct Mailbox;
+}
+
 namespace IPC {
 class Message;
 }  // namespace IPC
@@ -92,7 +96,7 @@ class CONTENT_EXPORT BrowserPluginGuestManager :
   void OnUnhandledSwapBuffersACK(int instance_id,
                                  int route_id,
                                  int gpu_host_id,
-                                 const std::string& mailbox_name,
+                                 const gpu::Mailbox& mailbox_name,
                                  uint32 sync_point);
 
   // Static factory instance (always NULL outside of tests).
diff --git a/content/browser/gpu/gpu_process_host_ui_shim.cc b/content/browser/gpu/gpu_process_host_ui_shim.cc
index 4e1a26e2..1fa06e6 100644
--- a/content/browser/gpu/gpu_process_host_ui_shim.cc
+++ b/content/browser/gpu/gpu_process_host_ui_shim.cc
@@ -321,10 +321,6 @@ void GpuProcessHostUIShim::OnAcceleratedSurfaceBuffersSwapped(
       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)
@@ -353,10 +349,6 @@ void GpuProcessHostUIShim::OnAcceleratedSurfacePostSubBuffer(
       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/image_transport_factory.cc b/content/browser/renderer_host/image_transport_factory.cc
index e37ea28..1027e2b 100644
--- a/content/browser/renderer_host/image_transport_factory.cc
+++ b/content/browser/renderer_host/image_transport_factory.cc
@@ -162,32 +162,23 @@ class ImageTransportClientTexture : public OwnedTexture {
                      host_context->createTexture()) {
   }
 
-  virtual void Consume(const std::string& mailbox_name,
+  virtual void Consume(const gpu::Mailbox& mailbox_name,
                        const gfx::Size& new_size) OVERRIDE {
-    DCHECK(mailbox_name.size() == GL_MAILBOX_SIZE_CHROMIUM);
-    mailbox_name_ = mailbox_name;
-    if (mailbox_name.empty())
-      return;
-
     DCHECK(host_context_ && texture_id_);
+    mailbox_name_ = mailbox_name;
     host_context_->bindTexture(GL_TEXTURE_2D, texture_id_);
-    host_context_->consumeTextureCHROMIUM(
-        GL_TEXTURE_2D,
-        reinterpret_cast<const signed char*>(mailbox_name.c_str()));
+    host_context_->consumeTextureCHROMIUM(GL_TEXTURE_2D, mailbox_name.name);
     size_ = new_size;
     host_context_->shallowFlushCHROMIUM();
   }
 
-  virtual std::string Produce() OVERRIDE {
-    std::string name;
-    if (!mailbox_name_.empty()) {
-      DCHECK(host_context_ && texture_id_);
-      host_context_->bindTexture(GL_TEXTURE_2D, texture_id_);
-      host_context_->produceTextureCHROMIUM(
-          GL_TEXTURE_2D,
-          reinterpret_cast<const signed char*>(mailbox_name_.c_str()));
-      mailbox_name_.swap(name);
-    }
+  virtual gpu::Mailbox Produce() OVERRIDE {
+    DCHECK(!mailbox_name_.IsZero());
+    DCHECK(host_context_ && texture_id_);
+    host_context_->bindTexture(GL_TEXTURE_2D, texture_id_);
+    host_context_->produceTextureCHROMIUM(GL_TEXTURE_2D, mailbox_name_.name);
+    gpu::Mailbox name;
+    std::swap(mailbox_name_, name);
     return name;
   }
 
@@ -195,7 +186,7 @@ class ImageTransportClientTexture : public OwnedTexture {
   virtual ~ImageTransportClientTexture() {}
 
  private:
-  std::string mailbox_name_;
+  gpu::Mailbox mailbox_name_;
   DISALLOW_COPY_AND_ASSIGN(ImageTransportClientTexture);
 };
 
diff --git a/content/browser/renderer_host/render_widget_host_view_android.cc b/content/browser/renderer_host/render_widget_host_view_android.cc
index 8b08ad3..5573cb3 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.cc
+++ b/content/browser/renderer_host/render_widget_host_view_android.cc
@@ -40,7 +40,7 @@ namespace content {
 namespace {
 
 void InsertSyncPointAndAckForGpu(
-    int gpu_host_id, int route_id, const std::string& return_mailbox) {
+    int gpu_host_id, int route_id, const gpu::Mailbox& return_mailbox) {
   uint32 sync_point =
       ImageTransportFactoryAndroid::GetInstance()->InsertSyncPoint();
   AcceleratedSurfaceMsg_BufferPresented_Params ack_params;
@@ -496,26 +496,13 @@ void RenderWidgetHostViewAndroid::OnSwapCompositorFrame(
 void RenderWidgetHostViewAndroid::AcceleratedSurfaceBuffersSwapped(
     const GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params& params,
     int gpu_host_id) {
-  if (params.mailbox_name.empty())
+  if (params.mailbox_name.IsZero())
     return;
 
-  std::string return_mailbox;
-  if (!current_mailbox_.IsZero()) {
-    return_mailbox.assign(
-        reinterpret_cast<const char*>(current_mailbox_.name),
-        sizeof(current_mailbox_.name));
-  }
-
   base::Closure callback = base::Bind(&InsertSyncPointAndAckForGpu,
                                       gpu_host_id, params.route_id,
-                                      return_mailbox);
-
-  gpu::Mailbox mailbox;
-  std::copy(params.mailbox_name.data(),
-            params.mailbox_name.data() + params.mailbox_name.length(),
-            reinterpret_cast<char*>(mailbox.name));
-
-  BuffersSwapped(mailbox, params.size, callback);
+                                      current_mailbox_);
+  BuffersSwapped(params.mailbox_name, params.size, callback);
 }
 
 void RenderWidgetHostViewAndroid::BuffersSwapped(
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 d4accf4..643ef00 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.cc
+++ b/content/browser/renderer_host/render_widget_host_view_aura.cc
@@ -289,10 +289,7 @@ void SendCompositorFrameAck(
   ack.gl_frame_data.reset(new cc::GLFrameData());
   DCHECK(!texture_to_produce || !skip_frame);
   if (texture_to_produce) {
-    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 =
         content::ImageTransportFactory::GetInstance()->InsertSyncPoint();
@@ -310,7 +307,7 @@ 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;
@@ -1164,7 +1161,7 @@ void RenderWidgetHostViewAura::UpdateExternalTexture() {
 bool RenderWidgetHostViewAura::SwapBuffersPrepare(
     const gfx::Rect& surface_rect,
     const gfx::Rect& damage_rect,
-    const std::string& mailbox_name,
+    const gpu::Mailbox& mailbox_name,
     const BufferPresentedCallback& ack_callback) {
   if (last_swapped_surface_size_ != surface_rect.size()) {
     // The surface could have shrunk since we skipped an update, in which
@@ -1175,7 +1172,7 @@ bool RenderWidgetHostViewAura::SwapBuffersPrepare(
   }
 
   if (ShouldSkipFrame(ConvertSizeToDIP(this, surface_rect.size())) ||
-      mailbox_name.empty()) {
+      mailbox_name.IsZero()) {
     skipped_damage_.op(RectToSkIRect(damage_rect), SkRegion::kUnion_Op);
     ack_callback.Run(true, scoped_refptr<ui::Texture>());
     return false;
@@ -1317,16 +1314,13 @@ void RenderWidgetHostViewAura::OnSwapCompositorFrame(
   ImageTransportFactory* factory = ImageTransportFactory::GetInstance();
   factory->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, mailbox_name, ack_callback);
+      frame->gl_frame_data->size, frame->gl_frame_data->mailbox, ack_callback);
 }
 
 void RenderWidgetHostViewAura::BuffersSwapped(
     const gfx::Size& size,
-    const std::string& mailbox_name,
+    const gpu::Mailbox& mailbox_name,
     const BufferPresentedCallback& ack_callback) {
   scoped_refptr<ui::Texture> texture_to_return(current_surface_);
   const gfx::Rect surface_rect = gfx::Rect(gfx::Point(), size);
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 3e07745..73903a5 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.h
+++ b/content/browser/renderer_host/render_widget_host_view_aura.h
@@ -44,6 +44,10 @@ class Canvas;
 class Display;
 }
 
+namespace gpu {
+struct Mailbox;
+}
+
 namespace ui {
 class CompositorLock;
 class InputMethod;
@@ -360,12 +364,12 @@ class RenderWidgetHostViewAura
   // The common entry point for full buffer updates from renderer
   // and GPU process.
   void BuffersSwapped(const gfx::Size& size,
-                      const std::string& mailbox_name,
+                      const gpu::Mailbox& mailbox_name,
                       const BufferPresentedCallback& ack_callback);
 
   bool SwapBuffersPrepare(const gfx::Rect& surface_rect,
                           const gfx::Rect& damage_rect,
-                          const std::string& mailbox_name,
+                          const gpu::Mailbox& mailbox_name,
                           const BufferPresentedCallback& ack_callback);
 
   void SwapBuffersCompleted(
diff --git a/content/common/browser_plugin/browser_plugin_messages.h b/content/common/browser_plugin/browser_plugin_messages.h
index dd8e2b2..fb7e331 100644
--- a/content/common/browser_plugin/browser_plugin_messages.h
+++ b/content/common/browser_plugin/browser_plugin_messages.h
@@ -14,6 +14,7 @@
 #include "content/common/content_export.h"
 #include "content/common/content_param_traits.h"
 #include "content/public/common/common_param_traits.h"
+#include "gpu/command_buffer/common/mailbox.h"
 #include "ipc/ipc_channel_handle.h"
 #include "ipc/ipc_message_macros.h"
 #include "ipc/ipc_message_utils.h"
@@ -207,7 +208,7 @@ IPC_MESSAGE_ROUTED5(BrowserPluginHostMsg_BuffersSwappedACK,
                     int /* instance_id */,
                     int /* route_id */,
                     int /* gpu_host_id */,
-                    std::string /* mailbox_name */,
+                    gpu::Mailbox /* mailbox_name */,
                     uint32 /* sync_point */)
 
 // When a BrowserPlugin has been removed from the embedder's DOM, it informs
@@ -384,7 +385,7 @@ IPC_MESSAGE_CONTROL2(BrowserPluginMsg_UpdatedName,
 IPC_MESSAGE_CONTROL5(BrowserPluginMsg_BuffersSwapped,
                      int /* instance_id */,
                      gfx::Size /* size */,
-                     std::string /* mailbox_name */,
+                     gpu::Mailbox /* mailbox_name */,
                      int /* route_id */,
                      int /* gpu_host_id */)
 
diff --git a/content/common/gpu/gpu_messages.h b/content/common/gpu/gpu_messages.h
index feef8e8..20b3b9d 100644
--- a/content/common/gpu/gpu_messages.h
+++ b/content/common/gpu/gpu_messages.h
@@ -19,6 +19,7 @@
 #include "content/public/common/gpu_memory_stats.h"
 #include "gpu/command_buffer/common/command_buffer.h"
 #include "gpu/command_buffer/common/constants.h"
+#include "gpu/command_buffer/common/mailbox.h"
 #include "gpu/ipc/gpu_command_buffer_traits.h"
 #include "ipc/ipc_channel_handle.h"
 #include "ipc/ipc_message_macros.h"
@@ -48,7 +49,7 @@ 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_name)
   IPC_STRUCT_MEMBER(gfx::Size, size)
 #if defined(OS_MACOSX)
   IPC_STRUCT_MEMBER(gfx::PluginWindowHandle, window)
@@ -65,7 +66,7 @@ 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_name)
   IPC_STRUCT_MEMBER(gfx::Size, surface_size)
 #if defined(OS_MACOSX)
   IPC_STRUCT_MEMBER(gfx::PluginWindowHandle, window)
@@ -78,7 +79,7 @@ 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_name)
   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 a40b60d..186cc37 100644
--- a/content/common/gpu/texture_image_transport_surface.cc
+++ b/content/common/gpu/texture_image_transport_surface.cc
@@ -214,9 +214,7 @@ bool TextureImageTransportSurface::SwapBuffers() {
   DCHECK(backbuffer_.size == current_size_);
   GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params params;
   params.size = backbuffer_.size;
-  const MailboxName& name = backbuffer_.mailbox_name;
-  params.mailbox_name.assign(
-      reinterpret_cast<const char*>(&name), sizeof(name));
+  params.mailbox_name = backbuffer_.mailbox_name;
 
   glFlush();
   ProduceTexture(&backbuffer_);
@@ -256,9 +254,7 @@ bool TextureImageTransportSurface::PostSubBuffer(
   params.y = y;
   params.width = width;
   params.height = height;
-  const MailboxName& name = backbuffer_.mailbox_name;
-  params.mailbox_name.assign(
-      reinterpret_cast<const char*>(&name), sizeof(name));
+  params.mailbox_name = backbuffer_.mailbox_name;
 
   glFlush();
   ProduceTexture(&backbuffer_);
@@ -316,12 +312,10 @@ void TextureImageTransportSurface::OnBufferPresented(
 }
 
 void TextureImageTransportSurface::BufferPresentedImpl(
-    const std::string& mailbox_name) {
+    const gpu::Mailbox& mailbox_name) {
   DCHECK(!backbuffer_.service_id);
-  if (!mailbox_name.empty()) {
-    DCHECK(mailbox_name.length() == GL_MAILBOX_SIZE_CHROMIUM);
-    mailbox_name.copy(reinterpret_cast<char *>(&backbuffer_.mailbox_name),
-                      sizeof(MailboxName));
+  if (!mailbox_name.IsZero()) {
+    backbuffer_.mailbox_name = mailbox_name;
     ConsumeTexture(&backbuffer_);
   }
 
@@ -370,7 +364,7 @@ void TextureImageTransportSurface::ReleaseBackTexture() {
 
   glDeleteTextures(1, &backbuffer_.service_id);
   backbuffer_.service_id = 0;
-  backbuffer_.mailbox_name = MailboxName();
+  backbuffer_.mailbox_name = gpu::Mailbox();
   glFlush();
   CHECK_GL_ERROR();
 }
@@ -401,12 +395,13 @@ void TextureImageTransportSurface::CreateBackTexture() {
   }
 
   if (!backbuffer_.service_id) {
-    MailboxName new_mailbox_name;
-    MailboxName& name = backbuffer_.mailbox_name;
+    gpu::Mailbox& name = backbuffer_.mailbox_name;
     // This slot should be uninitialized.
-    DCHECK(!memcmp(&name, &new_mailbox_name, sizeof(MailboxName)));
+    DCHECK(name.IsZero());
+
+    MailboxName new_mailbox_name;
     mailbox_manager_->GenerateMailboxName(&new_mailbox_name);
-    name = new_mailbox_name;
+    name.SetName(new_mailbox_name.key);
     glGenTextures(1, &backbuffer_.service_id);
   }
 
@@ -449,13 +444,13 @@ void TextureImageTransportSurface::ConsumeTexture(Texture* texture) {
   DCHECK(!texture->service_id);
 
   scoped_ptr<TextureDefinition> definition(mailbox_manager_->ConsumeTexture(
-      GL_TEXTURE_2D, texture->mailbox_name));
+      GL_TEXTURE_2D, MailboxName(texture->mailbox_name)));
   if (definition.get()) {
     texture->service_id = definition->ReleaseServiceId();
     texture->size = gfx::Size(definition->level_infos()[0][0].width,
                              definition->level_infos()[0][0].height);
   } else {
-    texture->mailbox_name = MailboxName();
+    texture->mailbox_name = gpu::Mailbox();
   }
 }
 
@@ -489,12 +484,12 @@ void TextureImageTransportSurface::ProduceTexture(Texture* texture) {
   // at which point we consume the correct texture back.
   bool success = mailbox_manager_->ProduceTexture(
       GL_TEXTURE_2D,
-      texture->mailbox_name,
+      MailboxName(texture->mailbox_name),
       definition.release(),
       NULL);
   DCHECK(success);
   texture->service_id = 0;
-  texture->mailbox_name = MailboxName();
+  texture->mailbox_name = gpu::Mailbox();
 }
 
 }  // namespace content
diff --git a/content/common/gpu/texture_image_transport_surface.h b/content/common/gpu/texture_image_transport_surface.h
index b29a97a..8b0e266 100644
--- a/content/common/gpu/texture_image_transport_surface.h
+++ b/content/common/gpu/texture_image_transport_surface.h
@@ -10,6 +10,7 @@
 #include "base/basictypes.h"
 #include "content/common/gpu/gpu_command_buffer_stub.h"
 #include "content/common/gpu/image_transport_surface.h"
+#include "gpu/command_buffer/common/mailbox.h"
 #include "gpu/command_buffer/service/mailbox_manager.h"
 #include "gpu/command_buffer/service/texture_manager.h"
 #include "ui/gl/gl_context.h"
@@ -71,14 +72,14 @@ class TextureImageTransportSurface
 
     // The mailbox name for the current service_id. Needs to be unique per
     // GL texture and is invalid while service_id is zero.
-    gpu::gles2::MailboxName mailbox_name;
+    gpu::Mailbox mailbox_name;
   };
 
   virtual ~TextureImageTransportSurface();
   void CreateBackTexture();
   void AttachBackTextureToFBO();
   void ReleaseBackTexture();
-  void BufferPresentedImpl(const std::string& mailbox_name);
+  void BufferPresentedImpl(const gpu::Mailbox& mailbox_name);
   void ProduceTexture(Texture* texture);
   void ConsumeTexture(Texture* texture);
 
diff --git a/content/renderer/browser_plugin/browser_plugin.cc b/content/renderer/browser_plugin/browser_plugin.cc
index 779740b..e975a2f 100644
--- a/content/renderer/browser_plugin/browser_plugin.cc
+++ b/content/renderer/browser_plugin/browser_plugin.cc
@@ -400,7 +400,7 @@ void BrowserPlugin::OnAdvanceFocus(int instance_id, bool reverse) {
 
 void BrowserPlugin::OnBuffersSwapped(int instance_id,
                                      const gfx::Size& size,
-                                     std::string mailbox_name,
+                                     gpu::Mailbox mailbox_name,
                                      int gpu_route_id,
                                      int gpu_host_id) {
   DCHECK(instance_id == instance_id_);
diff --git a/content/renderer/browser_plugin/browser_plugin.h b/content/renderer/browser_plugin/browser_plugin.h
index 8e51a5b..0294231 100644
--- a/content/renderer/browser_plugin/browser_plugin.h
+++ b/content/renderer/browser_plugin/browser_plugin.h
@@ -26,6 +26,10 @@ struct BrowserPluginHostMsg_ResizeGuest_Params;
 struct BrowserPluginMsg_LoadCommit_Params;
 struct BrowserPluginMsg_UpdateRect_Params;
 
+namespace gpu {
+struct Mailbox;
+}
+
 namespace content {
 
 class BrowserPluginCompositingHelper;
@@ -309,7 +313,7 @@ class CONTENT_EXPORT BrowserPlugin :
   void OnAdvanceFocus(int instance_id, bool reverse);
   void OnBuffersSwapped(int instance_id,
                         const gfx::Size& size,
-                        std::string mailbox_name,
+                        gpu::Mailbox mailbox_name,
                         int gpu_route_id,
                         int gpu_host_id);
   void OnGuestContentWindowReady(int instance_id,
diff --git a/content/renderer/browser_plugin/browser_plugin_compositing_helper.cc b/content/renderer/browser_plugin/browser_plugin_compositing_helper.cc
index c52a68e..f98d489b 100644
--- a/content/renderer/browser_plugin/browser_plugin_compositing_helper.cc
+++ b/content/renderer/browser_plugin/browser_plugin_compositing_helper.cc
@@ -63,9 +63,9 @@ void BrowserPluginCompositingHelper::EnableCompositing(bool enable) {
 // We use a shared graphics context accessible from the main
 // thread to do it.
 void BrowserPluginCompositingHelper::FreeMailboxMemory(
-    const std::string& mailbox_name,
+    const gpu::Mailbox& mailbox_name,
     unsigned sync_point) {
-  if (mailbox_name.empty())
+  if (mailbox_name.IsZero())
     return;
 
   scoped_refptr<cc::ContextProvider> context_provider =
@@ -87,14 +87,12 @@ void BrowserPluginCompositingHelper::FreeMailboxMemory(
 
   unsigned texture_id = context->createTexture();
   context->bindTexture(GL_TEXTURE_2D, texture_id);
-  context->consumeTextureCHROMIUM(
-      GL_TEXTURE_2D,
-      reinterpret_cast<const int8*>(mailbox_name.data()));
+  context->consumeTextureCHROMIUM(GL_TEXTURE_2D, mailbox_name.name);
   context->deleteTexture(texture_id);
 }
 
 void BrowserPluginCompositingHelper::MailboxReleased(
-    const std::string& mailbox_name,
+    const gpu::Mailbox& mailbox_name,
     int gpu_route_id,
     int gpu_host_id,
     unsigned sync_point) {
@@ -156,7 +154,7 @@ void BrowserPluginCompositingHelper::OnContainerDestroy() {
 
 void BrowserPluginCompositingHelper::OnBuffersSwapped(
     const gfx::Size& size,
-    const std::string& mailbox_name,
+    const gpu::Mailbox& mailbox_name,
     int gpu_route_id,
     int gpu_host_id,
     float device_scale_factor) {
@@ -203,9 +201,9 @@ void BrowserPluginCompositingHelper::OnBuffersSwapped(
     texture_layer_->setBounds(device_scale_adjusted_size);
   }
 
-  bool current_mailbox_valid = !mailbox_name.empty();
+  bool current_mailbox_valid = !mailbox_name.IsZero();
   if (!last_mailbox_valid_) {
-    MailboxReleased(std::string(), gpu_route_id, gpu_host_id, 0);
+    MailboxReleased(gpu::Mailbox(), gpu_route_id, gpu_host_id, 0);
     if (!current_mailbox_valid)
       return;
   }
diff --git a/content/renderer/browser_plugin/browser_plugin_compositing_helper.h b/content/renderer/browser_plugin/browser_plugin_compositing_helper.h
index 998b739..8d9b1b2 100644
--- a/content/renderer/browser_plugin/browser_plugin_compositing_helper.h
+++ b/content/renderer/browser_plugin/browser_plugin_compositing_helper.h
@@ -17,6 +17,10 @@ class SolidColorLayer;
 class TextureLayer;
 }
 
+namespace gpu {
+struct Mailbox;
+}
+
 namespace WebKit {
 class WebPluginContainer;
 class WebLayer;
@@ -36,7 +40,7 @@ class CONTENT_EXPORT BrowserPluginCompositingHelper :
   void EnableCompositing(bool);
   void OnContainerDestroy();
   void OnBuffersSwapped(const gfx::Size& size,
-                        const std::string& mailbox_name,
+                        const gpu::Mailbox& mailbox_name,
                         int gpu_route_id,
                         int gpu_host_id,
                         float device_scale_factor);
@@ -46,9 +50,9 @@ class CONTENT_EXPORT BrowserPluginCompositingHelper :
   friend class base::RefCounted<BrowserPluginCompositingHelper>;
  private:
   ~BrowserPluginCompositingHelper();
-  void FreeMailboxMemory(const std::string& mailbox_name,
+  void FreeMailboxMemory(const gpu::Mailbox& mailbox_name,
                          unsigned sync_point);
-  void MailboxReleased(const std::string& mailbox_name,
+  void MailboxReleased(const gpu::Mailbox& mailbox_name,
                        int gpu_route_id,
                        int gpu_host_id,
                        unsigned sync_point);
diff --git a/content/renderer/browser_plugin/browser_plugin_manager_impl.cc b/content/renderer/browser_plugin/browser_plugin_manager_impl.cc
index ac9880e..40f9517 100644
--- a/content/renderer/browser_plugin/browser_plugin_manager_impl.cc
+++ b/content/renderer/browser_plugin/browser_plugin_manager_impl.cc
@@ -100,7 +100,7 @@ void BrowserPluginManagerImpl::OnPluginAtPositionRequest(
 void BrowserPluginManagerImpl::OnUnhandledSwap(const IPC::Message& message,
                                                int instance_id,
                                                const gfx::Size& size,
-                                               std::string mailbox_name,
+                                               gpu::Mailbox mailbox_name,
                                                int gpu_route_id,
                                                int gpu_host_id) {
   // After the BrowserPlugin object sends a destroy message to the
diff --git a/content/renderer/browser_plugin/browser_plugin_manager_impl.h b/content/renderer/browser_plugin/browser_plugin_manager_impl.h
index 2496474..b8505e3 100644
--- a/content/renderer/browser_plugin/browser_plugin_manager_impl.h
+++ b/content/renderer/browser_plugin/browser_plugin_manager_impl.h
@@ -16,6 +16,10 @@ namespace gfx {
 class Point;
 }
 
+namespace gpu {
+struct Mailbox;
+}
+
 namespace content {
 
 class BrowserPluginManagerImpl : public BrowserPluginManager {
@@ -46,7 +50,7 @@ class BrowserPluginManagerImpl : public BrowserPluginManager {
   void OnUnhandledSwap(const IPC::Message& message,
                        int instance_id,
                        const gfx::Size& size,
-                       std::string mailbox_name,
+                       gpu::Mailbox mailbox_name,
                        int gpu_route_id,
                        int gpu_host_id);
 
diff --git a/gpu/command_buffer/service/mailbox_manager.cc b/gpu/command_buffer/service/mailbox_manager.cc
index 9019393..ccc48eb 100644
--- a/gpu/command_buffer/service/mailbox_manager.cc
+++ b/gpu/command_buffer/service/mailbox_manager.cc
@@ -8,6 +8,7 @@
 
 #include "base/rand_util.h"
 #include "crypto/hmac.h"
+#include "gpu/command_buffer/common/mailbox.h"
 #include "gpu/command_buffer/service/gl_utils.h"
 #include "gpu/command_buffer/service/texture_definition.h"
 
@@ -19,6 +20,10 @@ MailboxName::MailboxName() {
   std::fill(signature, signature + sizeof(signature), 0);
 }
 
+MailboxName::MailboxName(const ::gpu::Mailbox& mailbox) {
+  std::copy(mailbox.name, mailbox.name + sizeof(mailbox.name), key);
+}
+
 MailboxManager::MailboxManager()
     : hmac_(crypto::HMAC::SHA256),
       textures_(std::ptr_fun(&MailboxManager::TargetNameLess)) {
diff --git a/gpu/command_buffer/service/mailbox_manager.h b/gpu/command_buffer/service/mailbox_manager.h
index 8f97dd4..85a5ec0 100644
--- a/gpu/command_buffer/service/mailbox_manager.h
+++ b/gpu/command_buffer/service/mailbox_manager.h
@@ -22,6 +22,9 @@
 typedef signed char GLbyte;
 
 namespace gpu {
+
+struct Mailbox;
+
 namespace gles2 {
 
 class TextureDefinition;
@@ -32,6 +35,7 @@ class TextureManager;
 // group. It is a random key signed with a hash of a private key.
 struct GPU_EXPORT MailboxName {
   MailboxName();
+  explicit MailboxName(const ::gpu::Mailbox& mailbox);
   GLbyte key[GL_MAILBOX_SIZE_CHROMIUM / 2];
   GLbyte signature[GL_MAILBOX_SIZE_CHROMIUM / 2];
 };
diff --git a/ui/compositor/DEPS b/ui/compositor/DEPS
index 95ad49f..165753a 100644
--- a/ui/compositor/DEPS
+++ b/ui/compositor/DEPS
@@ -3,6 +3,7 @@
 # Compositor out of WebKit.
 include_rules = [
   "+cc",
+  "+gpu/command_buffer/common/mailbox.h",
   "+third_party/WebKit/Source/Platform/chromium/public",
   "+third_party/WebKit/Source/WebKit/chromium/public",
   "+webkit/glue",
diff --git a/ui/compositor/compositor.cc b/ui/compositor/compositor.cc
index 4cb9122..e28945f 100644
--- a/ui/compositor/compositor.cc
+++ b/ui/compositor/compositor.cc
@@ -11,7 +11,6 @@
 #include "base/command_line.h"
 #include "base/memory/singleton.h"
 #include "base/message_loop.h"
-#include "base/string_util.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_restrictions.h"
 #include "cc/context_provider.h"
@@ -20,6 +19,7 @@
 #include "cc/layer_tree_host.h"
 #include "cc/output_surface.h"
 #include "cc/thread_impl.h"
+#include "gpu/command_buffer/common/mailbox.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/compositor/compositor_observer.h"
 #include "ui/compositor/compositor_switches.h"
@@ -262,8 +262,8 @@ Texture::Texture(bool flipped, const gfx::Size& size, float device_scale_factor)
 Texture::~Texture() {
 }
 
-std::string Texture::Produce() {
-  return EmptyString();
+gpu::Mailbox Texture::Produce() {
+  return gpu::Mailbox();
 }
 
 CompositorLock::CompositorLock(Compositor* compositor)
diff --git a/ui/compositor/compositor.gyp b/ui/compositor/compositor.gyp
index 63143fc..26bfddc 100644
--- a/ui/compositor/compositor.gyp
+++ b/ui/compositor/compositor.gyp
@@ -14,6 +14,7 @@
         '<(DEPTH)/base/base.gyp:base',
         '<(DEPTH)/base/third_party/dynamic_annotations/dynamic_annotations.gyp:dynamic_annotations',
         '<(DEPTH)/cc/cc.gyp:cc',
+        '<(DEPTH)/gpu/gpu.gyp:gpu',
         '<(DEPTH)/skia/skia.gyp:skia',
         '<(DEPTH)/third_party/WebKit/Source/WebKit/chromium/WebKit.gyp:webkit',
         '<(DEPTH)/ui/gl/gl.gyp:gl',
diff --git a/ui/compositor/compositor.h b/ui/compositor/compositor.h
index 1f263e2..83c34b4d 100644
--- a/ui/compositor/compositor.h
+++ b/ui/compositor/compositor.h
@@ -35,6 +35,10 @@ class Point;
 class Rect;
 }
 
+namespace gpu {
+struct Mailbox;
+}
+
 namespace WebKit {
 class WebGraphicsContext3D;
 }
@@ -128,12 +132,12 @@ class COMPOSITOR_EXPORT Texture : public base::RefCounted<Texture> {
   virtual WebKit::WebGraphicsContext3D* HostContext3D() = 0;
 
   // Replaces the texture with the texture from the specified mailbox.
-  virtual void Consume(const std::string& mailbox_name,
+  virtual void Consume(const gpu::Mailbox& mailbox_name,
                        const gfx::Size& new_size) {}
 
   // Moves the texture into the mailbox and returns the mailbox name.
   // The texture must have been previously consumed from a mailbox.
-  virtual std::string Produce();
+  virtual gpu::Mailbox Produce();
 
  protected:
   virtual ~Texture();