Paper over a crash.

components/password_manager/content/browser/content_password_manager_driver_factory.cc

Index: components/password_manager/content/browser/content_password_manager_driver_factory.cc
diff --git a/components/password_manager/content/browser/content_password_manager_driver_factory.cc b/components/password_manager/content/browser/content_password_manager_driver_factory.cc
index 28c56eab09b63d684d264edc832647bebab11970..2ea51ead98e2539ccdca58343fd4a0823e963276 100644
--- a/components/password_manager/content/browser/content_password_manager_driver_factory.cc
+++ b/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);
 }