Maintain Diamond (F15) modifier state when rewriting.

chrome/browser/chromeos/events/event_rewriter.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_CHROMEOS_EVENTS_EVENT_REWRITER_H_
 #define CHROME_BROWSER_CHROMEOS_EVENTS_EVENT_REWRITER_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 161 matching lines @@
   std::map<int, DeviceType> device_id_to_type_;
 
   // The |source_device_id()| of the most recent keyboard event,
   // used to interpret modifiers on pointer events.
   int last_keyboard_device_id_;
 
   chromeos::input_method::ImeKeyboard* ime_keyboard_for_testing_;
   const PrefService* pref_service_for_testing_;
 
   // The sticky keys controller is not owned here;
-  // at time of writing it is a singleton in ash::Shell>
+  // at time of writing it is a singleton in ash::Shell.
   ash::StickyKeysController* sticky_keys_controller_;
 
+  // The ChromeOS Diamond key arrives as F15. Since F15 is not a modifier,
+  // we need to track its pressed state explicitly, and apply the selected
+  // modifier flag to key and mouse presses that arrive while F15 is down.
+  // While the Diamond key is down, this holds the corresponding modifier
+  // ui::EventFlags; otherwise it is EF_NONE.
+  int current_diamond_key_modifier_flags_;
+
   DISALLOW_COPY_AND_ASSIGN(EventRewriter);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_EVENTS_EVENT_REWRITER_H_