Add power-user keyboard mode for ChromeOS with Search key acting as a typical Fn key.

ash/accelerators/accelerator_table.cc

Index: ash/accelerators/accelerator_table.cc
diff --git a/ash/accelerators/accelerator_table.cc b/ash/accelerators/accelerator_table.cc
index 57ba21791c865c289c6fbf07a79c23c72bf48742..88d59dc6da5d02e459b39dffd7a2e5878b7fdb11 100644
--- a/ash/accelerators/accelerator_table.cc
+++ b/ash/accelerators/accelerator_table.cc
@@ -108,8 +108,10 @@ const AcceleratorData kAcceleratorData[] = {
     CYCLE_BACKWARD_LINEAR },
   { true, ui::VKEY_T, ui::EF_SHIFT_DOWN | ui::EF_CONTROL_DOWN, RESTORE_TAB },
   { true, ui::VKEY_PRINT, ui::EF_NONE, TAKE_SCREENSHOT },
-  // On Chrome OS, Search key is mapped to LWIN.
-  { true, ui::VKEY_LWIN, ui::EF_NONE, TOGGLE_APP_LIST },
+  // On Chrome OS, Search key is mapped to LWIN. The Search key binding should
+  // act on release instead of press, since the press can be eaten when using
+  // Search as a modifier key for extended keyboard shortcuts.
+  { false, ui::VKEY_LWIN, ui::EF_NONE, TOGGLE_APP_LIST },

[Yusuke Sato, 2012/11/26 22:22:57]

In patch set 4, you told me that you were going to enable the release
accelerator only when the feature is enabled. Could you do that?

I think we could do that in the following way:

1. have both press and release accelerators in this file.

 { true, ui::VKEY_LWIN, ui::EF_NONE, TOGGLE_APP_LIST },
 { false, ui::VKEY_LWIN, ui::EF_NONE, TOGGLE_APP_LIST },

2. modify accelerator_controller.cc so we can ignore Press+LWIN when the feature
is enabled, and we can also ignore Release+LWIN when the feature is disabled.

case TOGGLE_APP_LIST:
  if (the_feature_is_enabled &&
      accelerator.type() == Press &&
      accelerator.key_code() == LWIN) {
    return false;
  }
  if (!the_feature_is_enabled &&
      accelerator.type() == Release &&
      accelerator.key_code() == LWIN) {
    return false;
  }
  if (the_feature_is_enabled &&
      accelerator.type() == Release &&
      accelerator.key_code() == LWIN &&
      previous_event_type == ui::ET_KEY_RELEASED) {
    // If something else was pressed since the LWIN key, then we should ignore
the release of LWIN.
    return false;
  }

3. modify accelerator_controller_unittests.cc if needed.

[danakj, 2012/11/26 22:53:47]

Ah, right. To check if the feature is enabled, this code needs to access the
profile and switches which are in chrome/. And ash/ shouldn't be touching
chrome/ right?

Do you have any suggestion on how to plumb that setting into the controller?

Should I be doing this through ash::ShellDelegate? I see
IsSpokenFeedbackEnabled() there, which is the only thing that looks at all
similar.

[Yusuke Sato, 2012/11/26 23:01:49]

I'm not an ash owner, but I believe ShellDelegate is the right way to go.

   { true, ui::VKEY_MEDIA_LAUNCH_APP2, ui::EF_NONE, TOGGLE_APP_LIST },
   { true, ui::VKEY_LWIN, ui::EF_ALT_DOWN, TOGGLE_CAPS_LOCK },
   { true, ui::VKEY_VOLUME_MUTE, ui::EF_NONE, VOLUME_MUTE },