Initialize WakeLockContextHost lazily

content/browser/web_contents/web_contents_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/web_contents/web_contents_impl.h"
 
 #include <stddef.h>
 
 #include <cmath>
 #include <utility>
@@ skipping 463 matching lines @@
                  base::Unretained(this)));
 #if defined(OS_ANDROID)
   media_web_contents_observer_.reset(new MediaWebContentsObserverAndroid(this));
 #else
   media_web_contents_observer_.reset(new MediaWebContentsObserver(this));
 #endif
 #if BUILDFLAG(ENABLE_PLUGINS)
   pepper_playback_observer_.reset(new PepperPlaybackObserver(this));
 #endif
 
-  wake_lock_context_host_.reset(new WakeLockContextHost(this));
   loader_io_thread_notifier_.reset(new LoaderIOThreadNotifier(this));
   host_zoom_map_observer_.reset(new HostZoomMapObserver(this));
 }
 
 WebContentsImpl::~WebContentsImpl() {
   is_being_destroyed_ = true;
 
   // A WebContents should never be deleted while it is notifying observers,
   // since this will lead to a use-after-free as it continues to notfiy later
   // observers.
@@ skipping 1982 matching lines @@
 
   return guest->GetMainFrame();
 }
 
 device::GeolocationServiceContext*
 WebContentsImpl::GetGeolocationServiceContext() {
   return geolocation_service_context_.get();
 }
 
 device::mojom::WakeLockContext* WebContentsImpl::GetWakeLockServiceContext() {
+  if (!wake_lock_context_host_)
+    wake_lock_context_host_.reset(new WakeLockContextHost(this));
   return wake_lock_context_host_->GetWakeLockContext();
 }
 
 void WebContentsImpl::OnShowValidationMessage(
     RenderViewHostImpl* source,
     const gfx::Rect& anchor_in_root_view,
     const base::string16& main_text,
     const base::string16& sub_text) {
   // TODO(nick): Should we consider |source| here or pass it to the delegate?
   if (delegate_)
@@ skipping 2901 matching lines @@
     RenderViewHost* render_view_host = RenderViewHost::From(render_widget_host);
     if (!render_view_host)
       continue;
     render_view_host_set.insert(render_view_host);
   }
   for (RenderViewHost* render_view_host : render_view_host_set)
     render_view_host->OnWebkitPreferencesChanged();
 }
 
 }  // namespace content