<webview>: Move autosize from content to chrome.

BUG=330264
TBR=kenrb@chromium.org for browser_plugin_messages.h, kalman@chromium.org for guest_view_internal.json

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=287732

Review URL: https://codereview.chromium.org/427883002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@287822 0039d316-1c4b-4281-b951-d872f2087c98
24 files changed