Don't handle DCHECK failure in geofencing code.

content/child/geofencing/geofencing_dispatcher.cc

Index: content/child/geofencing/geofencing_dispatcher.cc
diff --git a/content/child/geofencing/geofencing_dispatcher.cc b/content/child/geofencing/geofencing_dispatcher.cc
index eec721faf979eaa18d6a140a076231195bb7f35d..57b4f036f61893f314a41c21e9c4fb1c2be05f6f 100644
--- a/content/child/geofencing/geofencing_dispatcher.cc
+++ b/content/child/geofencing/geofencing_dispatcher.cc
@@ -149,8 +149,6 @@ void GeofencingDispatcher::OnRegisterRegionComplete(int thread_id,
   blink::WebGeofencingCallbacks* callbacks =
       region_registration_requests_.Lookup(request_id);
   DCHECK(callbacks);
-  if (!callbacks)
-    return;
 
   if (status == GEOFENCING_STATUS_OK) {
     callbacks->onSuccess();
@@ -168,8 +166,6 @@ void GeofencingDispatcher::OnUnregisterRegionComplete(int thread_id,
   blink::WebGeofencingCallbacks* callbacks =
       region_unregistration_requests_.Lookup(request_id);
   DCHECK(callbacks);
-  if (!callbacks)
-    return;
 
   if (status == GEOFENCING_STATUS_OK) {
     callbacks->onSuccess();
@@ -189,8 +185,6 @@ void GeofencingDispatcher::OnGetRegisteredRegionsComplete(
   blink::WebGeofencingRegionsCallbacks* callbacks =
       get_registered_regions_requests_.Lookup(request_id);
   DCHECK(callbacks);
-  if (!callbacks)
-    return;
 
   if (status == GEOFENCING_STATUS_OK) {
     scoped_ptr<blink::WebVector<blink::WebGeofencingRegistration>> result(