Merge browser fixes

Summary:
Browser: fix nothing to do for "Done" button
The done key press was stolen in AddBookmarkPage.java.
The reason for this was, newline character will be added
as bookmark folder name. So to fix this issue, new line
character in keyboard was disabled. Also removed the
handling of key press in AddBookmarkPage.java.

Change-Id: I995a7e9cbc9301ea0b69b87f1a7dff304ea8fadd
CRs-Fixed: 571202

Fix exception in Browser Settings

Bug 11302175

Need to implement isValidFragment when targeting >= KK

Change-Id: I19cc285aa237ffd9001558a9ee6adaf152acd1df

Browser: Fix browser force close

Issue: Cursor was accessed by handler thread
       when it was closed. During Orientation change,
       BrowserBookmarksPage#onDestroyView is called
       which clears all the loaders [and cursors].
       Simultaneously ThreadedCursorAdapter#loadRowObject
       is getting called which then calls
       BrowserBookmarksAdapter#getRowObject
       where closed cursor is accessed and force close happens.

Fix: Synchronized cursors wrt main thread and handler thread.
     Checked mCursorAdapter for invalid conditions

CRs-Fixed: 576176
Change-Id: I9f16c2f1a55f35e8256bbf56afce3538850f9d42

Test Plan: test

Reviewers: synergy, jriordan001, raymanfx, donald.munn, rlasalle15, anders3408

Reviewed By: anders3408

CC: synergy

Differential Revision: http://review.codefirex.com/D276