Add mojo::StrongBindingSet and use it in GeolocationServiceContext.

content/browser/devtools/protocol/emulation_handler.cc

Index: content/browser/devtools/protocol/emulation_handler.cc
diff --git a/content/browser/devtools/protocol/emulation_handler.cc b/content/browser/devtools/protocol/emulation_handler.cc
index 7761ef6f6c943af6b00044927792154adc6d070e..b5acfd2b624e64858fc20bc7cc1ee9ed7938ffea 100644
--- a/content/browser/devtools/protocol/emulation_handler.cc
+++ b/content/browser/devtools/protocol/emulation_handler.cc
@@ -10,6 +10,7 @@
 #include "content/browser/renderer_host/render_widget_host_impl.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/common/view_messages.h"
+#include "content/public/common/geoposition.h"
 #include "content/public/common/url_constants.h"
 
 namespace content {
@@ -68,7 +69,7 @@ Response EmulationHandler::SetGeolocationOverride(
     return Response::InternalError("Could not connect to view");
 
   GeolocationServiceContext* geolocation_context =
-      GetWebContents()->GetGeolocationServiceContext();
+      GeolocationServiceContext::GetOrCreateForWebContents(GetWebContents());
   scoped_ptr<Geoposition> geoposition(new Geoposition());
   if (latitude && longitude && accuracy) {
     geoposition->latitude = *latitude;
@@ -90,8 +91,9 @@ Response EmulationHandler::ClearGeolocationOverride() {
     return Response::InternalError("Could not connect to view");
 
   GeolocationServiceContext* geolocation_context =
-      GetWebContents()->GetGeolocationServiceContext();
-  geolocation_context->ClearOverride();
+      GeolocationServiceContext::FromWebContents(GetWebContents());
+  if (geolocation_context)
+    geolocation_context->ClearOverride();
   return Response::OK();
 }