Revert of Always create top controls manager

cc/trees/layer_tree_host.cc

 // Copyright 2011 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/trees/layer_tree_host.h"
 
 #include <algorithm>
 #include <stack>
 #include <string>
 
@@ skipping 430 matching lines @@
       LayerTreeHostImpl::Create(settings_,
                                 client,
                                 proxy_.get(),
                                 rendering_stats_instrumentation_.get(),
                                 shared_bitmap_manager_,
                                 gpu_memory_buffer_manager_,
                                 id_);
   host_impl->SetUseGpuRasterization(UseGpuRasterization());
   shared_bitmap_manager_ = NULL;
   gpu_memory_buffer_manager_ = NULL;
-  top_controls_manager_weak_ptr_ =
-      host_impl->top_controls_manager()->AsWeakPtr();
+  if (settings_.calculate_top_controls_position &&
+      host_impl->top_controls_manager()) {
+    top_controls_manager_weak_ptr_ =
+        host_impl->top_controls_manager()->AsWeakPtr();
+  }
   input_handler_weak_ptr_ = host_impl->AsWeakPtr();
   return host_impl.Pass();
 }
 
 void LayerTreeHost::DidLoseOutputSurface() {
   TRACE_EVENT0("cc", "LayerTreeHost::DidLoseOutputSurface");
   DCHECK(proxy_->IsMainThread());
 
   if (output_surface_lost_)
     return;
@@ skipping 685 matching lines @@
   if (device_scale_factor == device_scale_factor_)
     return;
   device_scale_factor_ = device_scale_factor;
 
   SetNeedsCommit();
 }
 
 void LayerTreeHost::UpdateTopControlsState(TopControlsState constraints,
                                            TopControlsState current,
                                            bool animate) {
+  if (!settings_.calculate_top_controls_position)
+    return;
+
   // Top controls are only used in threaded mode.
   proxy_->ImplThreadTaskRunner()->PostTask(
       FROM_HERE,
       base::Bind(&TopControlsManager::UpdateTopControlsState,
                  top_controls_manager_weak_ptr_,
                  constraints,
                  current,
                  animate));
 }
 
@@ skipping 144 matching lines @@
     bool children_need_begin_frames) const {
   proxy_->SetChildrenNeedBeginFrames(children_need_begin_frames);
 }
 
 void LayerTreeHost::SendBeginFramesToChildren(
     const BeginFrameArgs& args) const {
   client_->SendBeginFramesToChildren(args);
 }
 
 }  // namespace cc