Add missing TaskScheduler on tests using RendereWidgetHostImpl

content/browser/renderer_host/render_widget_host_impl.cc

 // Copyright (c) 2012 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 "content/browser/renderer_host/render_widget_host_impl.h"
 
 #include <math.h>
 
 #include <set>
 #include <tuple>
@@ skipping 281 matching lines @@
       last_event_type_(blink::WebInputEvent::Undefined),
       new_content_rendering_delay_(
           base::TimeDelta::FromMilliseconds(kNewContentRenderingDelayMs)),
       current_content_source_id_(0),
       monitoring_composition_info_(false),
       weak_factory_(this) {
   CHECK(delegate_);
   CHECK_NE(MSG_ROUTING_NONE, routing_id_);
   latency_tracker_.SetDelegate(delegate_);
 
+  DCHECK(base::TaskScheduler::GetInstance())
+      << "Ref. Prerequisite section of post_task.h";
 #if defined(OS_WIN)
   // Update the display color profile cache so that it is likely to be up to
   // date when the renderer process requests the color profile.
   if (gfx::ICCProfile::CachedProfilesNeedUpdate()) {
     base::PostTaskWithTraits(
         FROM_HERE, base::TaskTraits().MayBlock().WithPriority(
                        base::TaskPriority::BACKGROUND),
         base::Bind(&gfx::ICCProfile::UpdateCachedProfilesOnBackgroundThread));
   }
 #endif
@@ skipping 2341 matching lines @@
 
   // After navigation, if a frame belonging to the new page is received, stop
   // the timer that triggers clearing the graphics of the last page.
   if (last_received_content_source_id_ >= current_content_source_id_ &&
       new_content_rendering_timeout_->IsRunning()) {
     new_content_rendering_timeout_->Stop();
   }
 }
 
 }  // namespace content