cc: Implement shared worker contexts.

ui/compositor/test/in_process_context_provider.cc

 // Copyright (c) 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 "ui/compositor/test/in_process_context_provider.h"
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
 #include "base/lazy_instance.h"
 #include "base/strings/stringprintf.h"
@@ skipping 67 matching lines @@
     : attribs_(attribs),
       gpu_memory_buffer_manager_(gpu_memory_buffer_manager),
       image_factory_(image_factory),
       window_(window),
       debug_name_(debug_name),
       destroyed_(false) {
   DCHECK(main_thread_checker_.CalledOnValidThread());
   context_thread_checker_.DetachFromThread();
 }
 
-InProcessContextProvider::~InProcessContextProvider() {
-  DCHECK(main_thread_checker_.CalledOnValidThread() ||
-         context_thread_checker_.CalledOnValidThread());
+InProcessContextProvider::~InProcessContextProvider() {}
+
+void InProcessContextProvider::Destroy() {
+  base::AutoLock lock(destroyed_lock_);
+  if (context_)
+    context_->SetContextLostCallback(base::Closure());
+  destroyed_ = true;
 }
 
 bool InProcessContextProvider::BindToCurrentThread() {
   // This is called on the thread the context will be used.
   DCHECK(context_thread_checker_.CalledOnValidThread());
 
   if (!context_) {
     gfx::GpuPreference gpu_preference = gfx::PreferDiscreteGpu;
     context_.reset(gpu::GLInProcessContext::Create(
         nullptr,                           /* service */
@@ skipping 124 matching lines @@
       return;
     destroyed_ = true;
   }
   if (!lost_context_callback_.is_null())
     base::ResetAndReturn(&lost_context_callback_).Run();
   if (gr_context_)
     gr_context_->abandonContext();
 }
 
 }  // namespace ui