[Android] Enable composited selection updates
Now that selection bounds are routed through the compositor, enable the feature
in Blink and hook the CompositorFrameMetadata-carried bounds into the existing
selection handle pipeline. Also suppress the sending of
ViewHostMsg_SelectionBoundsChanged messages when the feature is enabled.
This patch depends directly on
https://codereview.chromium.org/
454643002/.
BUG=135959
Review URL: https://codereview.chromium.org/
359033002
Cr-Commit-Position: refs/heads/master@{#296218}