Make ShaderTranslatorCache thread safe

mojo/services/gles2/command_buffer_impl.cc

 // Copyright 2013 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 "mojo/services/gles2/command_buffer_impl.h"
 
 #include "base/bind.h"
 #include "base/memory/shared_memory.h"
 
 #include "gpu/command_buffer/common/constants.h"
@@ skipping 78 matching lines @@
   scheduler_.reset(new gpu::GpuScheduler(
       command_buffer_.get(), decoder_.get(), decoder_.get()));
   decoder_->set_engine(scheduler_.get());
 
   gpu::gles2::DisallowedFeatures disallowed_features;
 
   // TODO(piman): attributes.
   std::vector<int32> attrib_vector;
   if (!decoder_->Initialize(surface,
                             context,
+                            new gpu::gles2::ShaderTranslatorCache,

[no sievers, 2014/04/02 18:30:19]

We don't actually have to create one per decoder, but can at least store it in
the ContextGroup, or even better maybe ShaderManager (owned by ContextGroup).

piman@ might further know if there is a good place for mojo to share this more
widely, in case creation cost in terms of time and memory for the translator is
still an issue nowadays.

[piman, 2014/04/02 21:58:33]

Currently, mojo support is still in its infancy. We don't support ContextGroups
yet (see TODOs above).
It's fine to create one per ContextGroup in mojo for now, just add a TODO(piman)
about it only needing to be per-thread?

                             false /* offscreen */,
                             size_,
                             disallowed_features,
                             attrib_vector))
     return false;
 
   gpu_control_.reset(
       new gpu::GpuControlService(context_group->image_manager(),
                                  NULL,
                                  context_group->mailbox_manager(),
@@ skipping 65 matching lines @@
 
 void CommandBufferImpl::OnParseError() {
   gpu::CommandBuffer::State state = command_buffer_->GetState();
   client_->LostContext(state.context_lost_reason);
 }
 
 void CommandBufferImpl::DrawAnimationFrame() { client_->DrawAnimationFrame(); }
 
 }  // namespace services
 }  // namespace mojo