Use FrameTreeNode ID as frameId in extension APIs

chrome/browser/extensions/api/web_navigation/web_navigation_api_helpers.cc

Index: chrome/browser/extensions/api/web_navigation/web_navigation_api_helpers.cc
diff --git a/chrome/browser/extensions/api/web_navigation/web_navigation_api_helpers.cc b/chrome/browser/extensions/api/web_navigation/web_navigation_api_helpers.cc
index 3b04125a35373f2826840b85c5a3914624cbc65d..3e00de089b43e95d96a521eba0c8392d339b77a6 100644
--- a/chrome/browser/extensions/api/web_navigation/web_navigation_api_helpers.cc
+++ b/chrome/browser/extensions/api/web_navigation/web_navigation_api_helpers.cc
@@ -19,6 +19,7 @@
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
 #include "extensions/browser/event_router.h"
+#include "extensions/browser/extension_api_frame_id_map.h"
 #include "extensions/common/event_filtering_info.h"
 #include "net/base/net_errors.h"
 #include "ui/base/page_transition_types.h"
@@ -60,15 +61,10 @@ void DispatchEvent(content::BrowserContext* browser_context,
 }  // namespace
 
 int GetFrameId(content::RenderFrameHost* frame_host) {
-  if (!frame_host)
-    return -1;
-  return !frame_host->GetParent() ? 0 : frame_host->GetRoutingID();
+  return ExtensionApiFrameIdMap::GetFrameId(frame_host).frame_id;
 }
 
 // Constructs and dispatches an onBeforeNavigate event.
-// TODO(dcheng): Is the parent process ID needed here? http://crbug.com/393640
-// Collisions are probably possible... but maybe this won't ever happen because
-// of the SiteInstance grouping policies.
 void DispatchOnBeforeNavigate(content::WebContents* web_contents,
                               content::RenderFrameHost* frame_host,
                               const GURL& validated_url) {