Remove keyIdentifier usage in chrome/browser/resources/*

This removes the majority of the keyIdentifier usages in the browser
resources. Replace the usage with the formally specified 'key' field.

No functional changes intended.

BUG=607349
NOPRESUBMIT=true
CQ_INCLUDE_TRYBOTS=tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2059913002
Cr-Commit-Position: refs/heads/master@{#399913}
35 files changed