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- Propagates the suggestions' group information, i.e., group IDs,
  associated headers, and current visibilities (determined by the prefs)
  to JS.
- Renders grouped matches under their associated header.
- Allows showing/hiding grouped suggestions and updates the prefs.

screenshot/zHMaQioPKVF
screenshot/6uiibJ6BLhm

Bug: 1052514
Change-Id: I8982ca0f3ce4d84121fffc8054e9190742af73e1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2145954
Commit-Queue: Moe Ahmadi <mahmadi@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Tommy Li <tommycli@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758950}