Revert of Pepper takes ownership of a mailbox before passing it to the texture layer.

content/renderer/pepper/ppb_graphics_3d_impl.cc

Index: content/renderer/pepper/ppb_graphics_3d_impl.cc
diff --git a/content/renderer/pepper/ppb_graphics_3d_impl.cc b/content/renderer/pepper/ppb_graphics_3d_impl.cc
index 35638b5d45f171bb5954534c14e947050049bb05..24c6513c12fb8119bb4d5ef6293d885dcc83d5e9 100644
--- a/content/renderer/pepper/ppb_graphics_3d_impl.cc
+++ b/content/renderer/pepper/ppb_graphics_3d_impl.cc
@@ -28,7 +28,6 @@
 #include "third_party/WebKit/public/web/WebElement.h"
 #include "third_party/WebKit/public/web/WebLocalFrame.h"
 #include "third_party/WebKit/public/web/WebPluginContainer.h"
-#include "third_party/khronos/GLES2/gl2.h"
 
 using ppapi::thunk::EnterResourceNoLock;
 using ppapi::thunk::PPB_Graphics3D_API;
@@ -115,23 +114,6 @@
   command_buffer_->EnsureWorkVisible();
 }
 
-void PPB_Graphics3D_Impl::TakeFrontBuffer() {
-  if (!taken_front_buffer_.IsZero()) {
-    DLOG(ERROR)
-        << "TakeFrontBuffer should only be called once before DoSwapBuffers";
-    return;
-  }
-  taken_front_buffer_ = GenerateMailbox();
-  command_buffer_->TakeFrontBuffer(taken_front_buffer_);
-}
-
-void PPB_Graphics3D_Impl::ReturnFrontBuffer(const gpu::Mailbox& mailbox,
-                                            const gpu::SyncToken& sync_token,
-                                            bool is_lost) {
-  command_buffer_->ReturnFrontBuffer(mailbox, sync_token, is_lost);
-  mailboxes_to_reuse_.push_back(mailbox);
-}
-
 bool PPB_Graphics3D_Impl::BindToInstance(bool bind) {
   bound_to_instance_ = bind;
   return true;
@@ -161,10 +143,8 @@
 
 int32_t PPB_Graphics3D_Impl::DoSwapBuffers(const gpu::SyncToken& sync_token) {
   DCHECK(command_buffer_);
-  if (taken_front_buffer_.IsZero()) {
-    DLOG(ERROR) << "TakeFrontBuffer should be called before DoSwapBuffers";
-    return PP_ERROR_FAILED;
-  }
+  if (sync_token.HasData())
+    sync_token_ = sync_token;
 
   if (bound_to_instance_) {
     // If we are bound to the instance, we need to ask the compositor
@@ -174,18 +154,14 @@
     //
     // Don't need to check for NULL from GetPluginInstance since when we're
     // bound, we know our instance is valid.
-    cc::TextureMailbox texture_mailbox(taken_front_buffer_, sync_token,
-                                       GL_TEXTURE_2D);
-    taken_front_buffer_.SetZero();
-    HostGlobals::Get()
-        ->GetInstance(pp_instance())
-        ->CommitTextureMailbox(texture_mailbox);
+    HostGlobals::Get()->GetInstance(pp_instance())->CommitBackingTexture();
     commit_pending_ = true;
   } else {
     // Wait for the command to complete on the GPU to allow for throttling.
     command_buffer_->SignalSyncToken(
-        sync_token, base::Bind(&PPB_Graphics3D_Impl::OnSwapBuffers,
-                               weak_ptr_factory_.GetWeakPtr()));
+        sync_token_,
+        base::Bind(&PPB_Graphics3D_Impl::OnSwapBuffers,
+                   weak_ptr_factory_.GetWeakPtr()));
   }
 
   return PP_OK_COMPLETIONPENDING;
@@ -286,6 +262,10 @@
   if (command_buffer_id)
     *command_buffer_id = command_buffer_->GetCommandBufferID();
 
+  mailbox_ = gpu::Mailbox::Generate();
+  if (!command_buffer_->ProduceFrontBuffer(mailbox_))
+    return false;
+
   return true;
 }
 
@@ -359,14 +339,4 @@
     ppp_graphics_3d->Graphics3DContextLost(this_pp_instance);
 }
 
-gpu::Mailbox PPB_Graphics3D_Impl::GenerateMailbox() {
-  if (!mailboxes_to_reuse_.empty()) {
-    gpu::Mailbox mailbox = mailboxes_to_reuse_.back();
-    mailboxes_to_reuse_.pop_back();
-    return mailbox;
-  }
-
-  return gpu::Mailbox::Generate();
-}
-
 }  // namespace content