Clean up event flags a bit:

components/exo/keyboard.cc

 // Copyright 2015 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.
 
 #include "components/exo/keyboard.h"
 
 #include "ash/shell.h"
 #include "components/exo/keyboard_delegate.h"
 #include "components/exo/surface.h"
 #include "ui/aura/client/focus_client.h"
@@ skipping 18 matching lines @@
     focus_->RemoveSurfaceObserver(this);
   aura::client::GetFocusClient(ash::Shell::GetPrimaryRootWindow())
       ->RemoveObserver(this);
   ash::Shell::GetInstance()->RemovePreTargetHandler(this);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // ui::EventHandler overrides:
 
 void Keyboard::OnKeyEvent(ui::KeyEvent* event) {
-  const int kModifierMask = ui::EF_CAPS_LOCK_DOWN | ui::EF_SHIFT_DOWN |
-                            ui::EF_CONTROL_DOWN | ui::EF_ALT_DOWN |
-                            ui::EF_COMMAND_DOWN | ui::EF_ALTGR_DOWN |
-                            ui::EF_MOD3_DOWN | ui::EF_NUM_LOCK_DOWN;
+  const int kModifierMask =
+      ui::EF_SHIFT_DOWN | ui::EF_CONTROL_DOWN | ui::EF_ALT_DOWN |
+      ui::EF_COMMAND_DOWN | ui::EF_ALTGR_DOWN | ui::EF_MOD3_DOWN |
+      ui::EF_NUM_LOCK_ON | ui::EF_CAPS_LOCK_ON | ui::EF_SCROLL_LOCK_ON;

[reveman, 2016/01/07 12:02:59]

nit: please avoid adding ui::EF_SCROLL_LOCK_ON as part of this patch as it
requires additional changes to the wayland code to avoid sending unnecessary
modifier events. ie. if scroll lock state changes then we'll send modifier
events to wayland clients without any modifiers that the client is aware of
actually changing.

[Peter Kasting, 2016/01/07 12:15:24]

Oh, I thought you had told me this would have no effect.  Sure, I'll remove it
from this change then.

Do you want me to write a separate change for this, or do something else?

[reveman, 2016/01/07 12:32:36]

Sorry, I failed to think of this before. It wouldn't break anything but it would
have a subtle change in behavior which I think is best to avoid as part of this
patch.
It would be more correct to move this into the wayland code (ie. move this
modifider mask to the KeyboardDelegate) but I think we can just leave this as is
for now.

   int modifier_flags = event->flags() & kModifierMask;
   if (modifier_flags != modifier_flags_) {
     modifier_flags_ = modifier_flags;
     if (focus_)
       delegate_->OnKeyboardModifiers(modifier_flags_);
   }
 
   switch (event->type()) {
     case ui::ET_KEY_PRESSED: {
       auto it =
@@ skipping 57 matching lines @@
 
 Surface* Keyboard::GetEffectiveFocus(aura::Window* window) const {
   Surface* focus = Surface::AsSurface(window);
   if (!focus)
     return nullptr;
 
   return delegate_->CanAcceptKeyboardEventsForSurface(focus) ? focus : nullptr;
 }
 
 }  // namespace exo