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Copies ContentView from components and EventOffsetHandler from chrome.
These together will call EventForwarder.setCurrentTouchEventOffsets at
the right times to correctly offset user input under browser controls

Change-Id: I29a418457c4daf2306e7ce13e8311a489b1ca958
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1796046Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Bo <boliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#695823}