Cherry pick: Attach ImeAdapter in CVC initialization.

This is a clean cherry pick from:
https://crrev.com/06091eaf4543692caf7a0bcaf5c3a550dfca7078

We need to do this because in the Android WebView pop up flow, the
native WebContents object could possibly have received RenderViewReady
IPC message before the CVC is constructed and starts to observe the
WebContents.

BUG: 18527015
Change-Id: Ibccac065c0607bd2ec45c0a9e152128ea8805b7e
1 file changed