Added completion notification to Profile's ClearNetworkingHistorySince.

chrome/browser/profiles/off_the_record_profile_impl.cc

Index: chrome/browser/profiles/off_the_record_profile_impl.cc
diff --git a/chrome/browser/profiles/off_the_record_profile_impl.cc b/chrome/browser/profiles/off_the_record_profile_impl.cc
index 75d42a62520d1dfa419c5cc24a9833f88e5261a2..b691ae209907aa39c4f74b09cb18656d5f240e47 100644
--- a/chrome/browser/profiles/off_the_record_profile_impl.cc
+++ b/chrome/browser/profiles/off_the_record_profile_impl.cc
@@ -452,8 +452,14 @@ chrome_browser_net::Predictor* OffTheRecordProfileImpl::GetNetworkPredictor() {
   return NULL;
 }
 
-void OffTheRecordProfileImpl::ClearNetworkingHistorySince(base::Time time) {
-  // No need to do anything here, our transport security state is read-only.
+void OffTheRecordProfileImpl::ClearNetworkingHistorySince(
+    base::Time time,
+    const base::Closure& completion) {
+  // No need to do anything here, our transport security state is read-only, but
+  // fire the callback to be on the safe side.
+  if (!completion.is_null()) {
+    completion.Run();
+  }
 }
 
 GURL OffTheRecordProfileImpl::GetHomePage() {