Modify the "dangerous download" algorithm as follows. Original patch by Pier...

chrome/common/navigation_gesture.h

Index: chrome/common/navigation_gesture.h
===================================================================
--- chrome/common/navigation_gesture.h	(revision 68377)
+++ chrome/common/navigation_gesture.h	(working copy)
@@ -7,17 +7,13 @@
 #pragma once
 
 enum NavigationGesture {
-  NavigationGestureUser,    // User initiated navigation/load. This is not
-                            // currently used due to the untrustworthy nature
-                            // of userGestureHint (wasRunByUserGesture). See
-                            // bug 1051891.
+  NavigationGestureUser,    // User initiated navigation/load.
   NavigationGestureAuto,    // Non-user initiated navigation / load. For example
                             // onload or setTimeout triggered document.location
                             // changes, and form.submits. See bug 1046841 for
                             // some cases that should be treated this way but
                             // aren't yet.
-  NavigationGestureUnknown, // What we assign when userGestureHint returns true
-                            // because we can't trust it.
+  NavigationGestureUnknown, // Initial state.
 };
 
 #endif  // CHROME_COMMON_NAVIGATION_GESTURE_H_