Produce deterministic JSON output in mastermap by sorting keys.
Produce deterministic JSON output in mastermap by sorting keys.

R=luqui@chromium.org,dnj@chromium.org
BUG=459348

Review URL: https://codereview.chromium.org/945143005

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@294160 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build