Revert 128889 - Update IME preferences outside the IME status button when Uber Tray is in use.

Revert 128889 - Update IME preferences outside the IME status button when Uber Tray is in use.

* browser_state_monitor.cc/h:

Added. The class which monitors a notification from the browser to keep track of the browser state (not logged in, logged in, etc.) and notify the current state to the input method manager. The class also updates the appropriate Chrome prefs (~/Local\ State or ~/Preferences) depending on the current browser state.

When Uber Tray is disabled via chrome://flags, the class does nothing. In the next CL, I'll remove all preference code from InputMethodButton and make browser_state_monitor.cc work regardless of whether Uber Tray is disabled or not.

* preferences.cc:

When Uber Tray is enabled, handle prefs::kLanguageCurrentInputMethod and prefs::kLanguagePreviousInputMethod prefs in the class.  preferences.cc is the standard place for checking the initial values of Chrome OS specific user prefs.

BUG=chromiun-os:28297
TEST=manual (not ready for writing unit tests. It will be done as part of 19655 very soon for R20). Checked test cases in http://code.google.com/p/chromium-os/issues/detail?id=19655#c11.

Review URL: https://chromiumcodereview.appspot.com/9852008

TBR=yusukes@google.com
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=128923