gpu: Do not call MakeCurrent in wait sync token callback.

gpu/ipc/service/gpu_command_buffer_stub.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/ipc/service/gpu_command_buffer_stub.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 1075 matching lines @@
   if (mailbox_manager->UsesSync() && MakeCurrent())
     mailbox_manager->PullTextureUpdates(sync_token);
   return false;
 }
 
 void GpuCommandBufferStub::OnWaitSyncTokenCompleted(
     const SyncToken& sync_token) {
   DCHECK(waiting_for_sync_point_);
   TRACE_EVENT_ASYNC_END1("gpu", "WaitSyncTokenCompleted", this,
                          "GpuCommandBufferStub", this);
+  // Don't call PullTextureUpdates here because we can't MakeCurrent if we're
+  // executing commands on another context. The WaitSyncToken command will run
+  // again and call PullTextureUpdates once this command buffer gets scheduled.
   waiting_for_sync_point_ = false;
-
-  gles2::MailboxManager* mailbox_manager = context_group_->mailbox_manager();
-  if (mailbox_manager->UsesSync() && MakeCurrent())
-    mailbox_manager->PullTextureUpdates(sync_token);
-
   executor_->SetScheduled(true);
   channel_->OnStreamRescheduled(stream_id_, true);
 }
 
 void GpuCommandBufferStub::OnCreateImage(
     const GpuCommandBufferMsg_CreateImage_Params& params) {
   TRACE_EVENT0("gpu", "GpuCommandBufferStub::OnCreateImage");
   const int32_t id = params.id;
   const gfx::GpuMemoryBufferHandle& handle = params.gpu_memory_buffer;
   const gfx::Size& size = params.size;
@@ skipping 117 matching lines @@
       command_buffer_->GetLastState().error == error::kLostContext)
     return;
 
   command_buffer_->SetContextLostReason(error::kUnknown);
   if (decoder_)
     decoder_->MarkContextLost(error::kUnknown);
   command_buffer_->SetParseError(error::kLostContext);
 }
 
 }  // namespace gpu