DevTools: [Elements] elements panel shortcuts should not interfere with input editing
DevTools: [Elements] elements panel shortcuts should not interfere with input editing

Elements panel should not execute its shortcuts while the user does
editing in some input.

Thus the patch fixes Ctrl-Z/Ctrl-Y behavior in input fields in elements
panel, e.g. in Device Mode "user agent".

BUG=469632
R=pfeldman

Review URL: https://codereview.chromium.org/997353004

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@192964 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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