Revert of cc: Use worker context for one-copy tile initialization.

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 104 matching lines @@
   capabilities_.gpu = context_->GetImplementation()->capabilities();
 
   std::string unique_context_name =
       base::StringPrintf("%s-%p", debug_name_.c_str(), context_.get());
   context_->GetImplementation()->TraceBeginCHROMIUM(
       "gpu_toplevel", unique_context_name.c_str());
 
   return true;
 }
 
-void InProcessContextProvider::DetachFromThread() {
-  context_thread_checker_.DetachFromThread();
-}
-
 cc::ContextProvider::Capabilities
 InProcessContextProvider::ContextCapabilities() {
   DCHECK(context_thread_checker_.CalledOnValidThread());
   return capabilities_;
 }
 
 gpu::gles2::GLES2Interface* InProcessContextProvider::ContextGL() {
   DCHECK(context_thread_checker_.CalledOnValidThread());
 
   return context_->GetImplementation();
@@ skipping 86 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