add a new set of commands to resize and position windows

https://docs.google.com/a/google.com/document/d/1iDSRQzYiF6xYKp2PuA8kBmghK7Ar0OZXQZFsaUBNgKw/edit?usp=sharing

Devtools side, add a new UI domain and methods:
method: getWindowForTarget, param: targetID, return: windowID, bounds.
method: setWindowBounds, param: windowID, bounds
method: getWindowBounds, param: windowID, return: bounds

bounds object: left, top, width, height, window_state (minimized, maximized, fullscreen, normal)

BUG=604324

Review-Url: https://codereview.chromium.org/2734123004
Cr-Commit-Position: refs/heads/master@{#463110}
7 files changed