Make RenderView not have to know about how PhishingClassifierDelegate.

chrome/renderer/safe_browsing/phishing_dom_feature_extractor.cc

Index: chrome/renderer/safe_browsing/phishing_dom_feature_extractor.cc
===================================================================
--- chrome/renderer/safe_browsing/phishing_dom_feature_extractor.cc	(revision 73993)
+++ chrome/renderer/safe_browsing/phishing_dom_feature_extractor.cc	(working copy)
@@ -146,11 +146,7 @@
   if (!cur_frame_) {
     WebKit::WebView* web_view = render_view_->webview();
     if (!web_view) {
-      // When the WebView is going away, the render view should have called
-      // CancelPendingExtraction() which should have stopped any pending work,
-      // so this case should not happen.
-      NOTREACHED();
-      RunCallback(false);
+      RunCallback(false);  // The WebView is going away.
       return;
     }
     cur_frame_ = web_view->mainFrame();