Require a process ID when looking up RFHs by FrameTreeNode ID.

chrome/browser/safe_browsing/safe_browsing_navigation_observer.cc

Index: chrome/browser/safe_browsing/safe_browsing_navigation_observer.cc
diff --git a/chrome/browser/safe_browsing/safe_browsing_navigation_observer.cc b/chrome/browser/safe_browsing/safe_browsing_navigation_observer.cc
index dc296f1574d22d4afec82ab106e0d626b23654a4..af988333ec8c609f61f5933d37fa76dbf0717485 100644
--- a/chrome/browser/safe_browsing/safe_browsing_navigation_observer.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_navigation_observer.cc
@@ -144,9 +144,11 @@ void SafeBrowsingNavigationObserver::DidStartNavigation(
   // incorrect when another frame is targeting this frame. Need to refine this
   // logic after the true initiator details are added to NavigationHandle
   // (https://crbug.com/651895).
+  int current_process_id =
+      navigation_handle->GetStartingSiteInstance()->GetProcess()->GetID();

[Charlie Reis, 2017/05/01 21:56:59]

This is only ok because it matches the limitations described in the comment
above.  All of this will go away as soon as we track initiators.

   content::RenderFrameHost* current_frame_host =
       navigation_handle->GetWebContents()->FindFrameByFrameTreeNodeId(
-          nav_event->frame_id);
+          nav_event->frame_id, current_process_id);
   // For browser initiated navigation (e.g. from address bar or bookmark), we
   // don't fill the source_url to prevent attributing navigation to the last
   // committed navigation.