Revert of Idle cleanup for worker context

cc/output/context_provider.cc

-// Copyright (c) 2016 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 "cc/output/context_provider.h"
-
-namespace cc {
-
-ContextProvider::ScopedContextLock::ScopedContextLock(
-    ContextProvider* context_provider)
-    : context_provider_(context_provider),
-      context_lock_(*context_provider_->GetLock()) {
-  // Allow current thread to use |context_provider_|.
-  context_provider_->DetachFromThread();
-  busy_ = context_provider_->CacheController()->ClientBecameBusy();
-}
-
-ContextProvider::ScopedContextLock::~ScopedContextLock() {
-  // Let ContextCacheController know we are no longer busy.
-  context_provider_->CacheController()->ClientBecameNotBusy(std::move(busy_));
-
-  // Allow usage by thread for which |context_provider_| is bound to.
-  context_provider_->DetachFromThread();
-}
-
-}  // namespace cc