Paper over a crash.

This quick fix is designed to make trunk more stable and to be easy to apply and revert as needed.

BUG=438951
TBR=vabr@chromium.org

Review URL: https://codereview.chromium.org/788323003

Cr-Commit-Position: refs/heads/master@{#308153}

components/autofill/content/browser/content_autofill_driver_factory.cc

@@ -90,6 +90,14 @@ void ContentAutofillDriverFactory::RenderFrameDeleted(
 void ContentAutofillDriverFactory::DidNavigateMainFrame(
     const content::LoadCommittedDetails& details,
     const content::FrameNavigateParams& params) {
+  // This shouldn't happen, but is causing a lot of crashes.
+  // See http://crbug.com/438951
+  if (frame_driver_map_.find(web_contents()->GetMainFrame()) ==
+          frame_driver_map_.end()) {
+    LOG(ERROR) << "Could not find ContentAutofillDriver for main frame";
+    return;
+  }
+
   frame_driver_map_[web_contents()->GetMainFrame()]->DidNavigateFrame(details,
                                                                       params);
 }

components/password_manager/content/browser/content_password_manager_driver_factory.cc

@@ -101,6 +101,14 @@ void ContentPasswordManagerDriverFactory::DidNavigateAnyFrame(
     content::RenderFrameHost* render_frame_host,
     const content::LoadCommittedDetails& details,
     const content::FrameNavigateParams& params) {
+  // This shouldn't happen, but is causing a lot of crashes.
+  // See http://crbug.com/438951
+  if (frame_driver_map_.find(render_frame_host) == frame_driver_map_.end()) {
+    LOG(ERROR) << "Could not find ContentPasswordManagerDriver for frame " <<
+        render_frame_host;
+    return;
+  }
+
   frame_driver_map_[render_frame_host]->DidNavigateFrame(details, params);
 }