Allow MainThreadEventQueue to call the RenderWidget directly.
Allocate the MainThreadEventQueue from the render widget allowing
a binding between then. This allows us to avoid
serialization/deserialization of events to IPC messages inside the
renderer. It also allows us to avoid jumping through a number of hoops
looking the input handler in a table. For example requesting a begin
main frame from the main thread doesn't require a hop to the compositor
and back to the main thread any more.
BUG=703344
Review-Url: https://codereview.chromium.org/2813683002
Cr-Commit-Position: refs/heads/master@{#466340}
20 files changed
