Migrate idle_manager.mojom to the new Mojo types

This CL converts implementations of idle_manager.mojom
both the browser process(IdleMonitor) and the renderer process
(IdleDetector) in idle_manager.mojom.

 - Change mojo::Binding with mojo::Receiver
 - Change IdleManagerPtr with mojo::Remote<IdleManager>

Bug: 955171
Change-Id: I5e5b33cef0ee01b86e44e0778dbb2cd5ab9ac45d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1750508
Commit-Queue: Gyuyoung Kim <gyuyoung@igalia.com>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Ken Rockot <rockot@google.com>
Cr-Commit-Position: refs/heads/master@{#686691}
8 files changed