Fix style nits in file-local TextInputModeMapSingleton

TBR=jamesr
R=yoichio
BUG=none

Review URL: https://codereview.chromium.org/90603002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237539 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237539
Provide meaningful error description for failed requests.

EOM

BUG=310310

Review URL: https://codereview.chromium.org/62003002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237540 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237540