[Android] Properly remove SuggestionSpan after composition

This CL:

1) Reads Spanned#SPAN_COMPOSING from Java side and propagate it to
   Blink (SuggestionMarker).
2) Removes SuggestionMarker which has this flag after IME done with

We want to remove these SuggestionMarkers for
- InputConnection#commitText()
- InputConnection#setComposingText()
- InputConnection#finishComposing()

Note that before caret move event is covered by finishComposing().

Bug: 907928
Change-Id: I6245d7a2d43f54e7272d5abf6ea46b53f2f57ce7
Reviewed-on: https://chromium-review.googlesource.com/c/1361727
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Changwan Ryu <changwan@chromium.org>
Reviewed-by: Xiaocheng Hu <xiaochengh@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Shimi Zhang <ctzsm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#616926}
22 files changed