Add mojo::StrongBindingSet and use it in GeolocationServiceContext.

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index 27a226f75bb71d1735f87fcc92dbe6362e16c32b..2836f044a7b64943c59a64af1fc980e984699152 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -397,7 +397,6 @@ WebContentsImpl::WebContentsImpl(BrowserContext* browser_context)
       is_subframe_(false),
       force_disable_overscroll_content_(false),
       last_dialog_suppressed_(false),
-      geolocation_service_context_(new GeolocationServiceContext()),
       accessibility_mode_(
           BrowserAccessibilityStateImpl::GetInstance()->accessibility_mode()),
       audio_stream_monitor_(this),
@@ -2080,10 +2079,6 @@ RenderFrameHost* WebContentsImpl::GetGuestByInstanceID(
   return guest->GetMainFrame();
 }
 
-GeolocationServiceContext* WebContentsImpl::GetGeolocationServiceContext() {
-  return geolocation_service_context_.get();
-}
-
 WakeLockServiceContext* WebContentsImpl::GetWakeLockServiceContext() {
   return wake_lock_service_context_.get();
 }