Title of RootInfo on ToolBar do not update after locale changed

RootInfo title of "Images" or "Videos" or "Audio" or "Downloads" do not
update after locale changed

Root Cause : BaseActivity.java
 1) onSaveInstanceState(Bundle state) : save the old state before locale changed
 2) onCreate.getState(icicle) : assign old state to mState => mState.stack.getRoot() is old locale

Solution :
 Update current root title from latest root

Bug: 37358441
Test: atest DocumentsUITests
      manual test swtich locale and observe toolbar update locale

Change-Id: Ib79d1885766ce76ae194196f9286ef5265734efa