Navigation throttle for the Safe Browsing Subresource Filter.

content/public/browser/navigation_handle.h

Index: content/public/browser/navigation_handle.h
diff --git a/content/public/browser/navigation_handle.h b/content/public/browser/navigation_handle.h
index 96b14ef6da138ec6f3241f3cab915ac7f10822ed..4188f0e51a095378a71d0eeac757362ac9b54a05 100644
--- a/content/public/browser/navigation_handle.h
+++ b/content/public/browser/navigation_handle.h
@@ -121,7 +121,9 @@ class CONTENT_EXPORT NavigationHandle {
   virtual net::Error GetNetErrorCode() = 0;
 
   // Returns the RenderFrameHost this navigation is taking place in. This can
-  // only be accessed after the navigation is ready to commit.
+  // only be accessed after the navigation starts processing the response.
+  // The RenderFrameHost returned back might not be the final one, if method is
+  // called before ReadyToCommitNavigation is dispatched.

[clamy, 2016/06/15 10:03:40]

This is not true in PlzNavigate, and in the current architecture we don't
currently dispatch ReadyToCommitNavigation.
@Nasko: do we have plans to dispatch ReadyToCommitNavigation after we make the
choice to transfer the navigation or not? I think it would be possible.
In that case, since the patch doesn't need to cancel/pause navigations, it could
be rewritten as a WebContentsObserver that only listens to DidRedirectNavigation
and ReadyToCommitNavigation.

   virtual RenderFrameHost* GetRenderFrameHost() = 0;
 
   // Whether the navigation happened in the same page. This is only known
@@ -183,6 +185,10 @@ class CONTENT_EXPORT NavigationHandle {
                                     const GURL& new_referrer_url,
                                     bool new_is_external_protocol) = 0;
 
+  // Simulates that throttle is about to process the response.
+  virtual NavigationThrottle::ThrottleCheckResult
+  CallWillProcessResponseForTesting(RenderFrameHost* render_frame_host) = 0;
+
   // The NavigationData that the embedder returned from
   // ResourceDispatcherHostDelegate::GetNavigationData during commit. This will
   // be a clone of the NavigationData.