Fix regression of webview loadstart events firing for same page navigations.

extensions/browser/guest_view/web_view/web_view_guest.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "extensions/browser/guest_view/web_view/web_view_guest.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 844 matching lines @@
   args->SetInteger(webview::kInternalProcessId,
                    web_contents()->GetRenderProcessHost()->GetID());
   DispatchEventToView(base::MakeUnique<GuestViewEvent>(
       webview::kEventLoadCommit, std::move(args)));
 
   find_helper_.CancelAllFindSessions();
 }
 
 void WebViewGuest::DidStartNavigation(
     content::NavigationHandle* navigation_handle) {
+  // loadStart shouldn't be sent for same page navigations.
+  if (navigation_handle->IsSamePage())
+    return;
+
   std::unique_ptr<base::DictionaryValue> args(new base::DictionaryValue());
   args->SetString(guest_view::kUrl, navigation_handle->GetURL().spec());
   args->SetBoolean(guest_view::kIsTopLevel, navigation_handle->IsInMainFrame());
   DispatchEventToView(base::MakeUnique<GuestViewEvent>(webview::kEventLoadStart,
                                                        std::move(args)));
 }
 
 void WebViewGuest::RenderProcessGone(base::TerminationStatus status) {
   // Cancel all find sessions in progress.
   find_helper_.CancelAllFindSessions();
@@ skipping 643 matching lines @@
     std::unique_ptr<base::DictionaryValue> args(new base::DictionaryValue());
     DispatchEventToView(base::MakeUnique<GuestViewEvent>(
         webview::kEventExitFullscreen, std::move(args)));
   }
   // Since we changed fullscreen state, sending a Resize message ensures that
   // renderer/ sees the change.
   web_contents()->GetRenderViewHost()->GetWidget()->WasResized();
 }
 
 }  // namespace extensions