Fix comment to match implementation.

content/browser/geolocation/geolocation_provider_impl.h

Index: content/browser/geolocation/geolocation_provider_impl.h
diff --git a/content/browser/geolocation/geolocation_provider_impl.h b/content/browser/geolocation/geolocation_provider_impl.h
index e3b8762ed445112e1a7c192000a701af587a4f39..d3cc1212000121ca74ce432c8c5985a7f6b75fb5 100644
--- a/content/browser/geolocation/geolocation_provider_impl.h
+++ b/content/browser/geolocation/geolocation_provider_impl.h
@@ -37,7 +37,7 @@ class CONTENT_EXPORT GeolocationProviderImpl
 
   // Gets a pointer to the singleton instance of the location relayer, which
   // is in turn bound to the browser's global context objects. This must only be
-  // called on the IO thread so that the GeolocationProviderImpl is always
+  // called on the UI thread so that the GeolocationProviderImpl is always
   // instantiated on the same thread. Ownership is NOT returned.
   static GeolocationProviderImpl* GetInstance();