[WebOTP] Show notification on omnibox when the API is called

This patch adds a ui controller to show a notification on omnibox when
the API is called. The exact string is TBD.

This patch also refactors the fetching remote sms logic which leads to
some other changes:
1. |SmsFetcherImpl| no longer needs a ref to |BrowserContext|.
2. The sms fetching request / response is now managed by the new sharing
controller to be consistent with ClickToCall and SharedClipBoard.

Design doc: https://docs.google.com/document/d/1SlIaRlH0WEvvLMtQJZMuwZbH5bRs6SCPlxXwwnJQHMU/edit?usp=sharing

Bug: 1015645
Change-Id: I606ef77f1c2b6719876f295dc9be263a978fea3e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2752372
Reviewed-by: Avi Drissman <[email protected]>
Reviewed-by: Majid Valipour <[email protected]>
Reviewed-by: Richard Knoll <[email protected]>
Commit-Queue: Yi Gu <[email protected]>
Cr-Commit-Position: refs/heads/master@{#864898}
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index 8c37e649..111e2e0b 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -3992,6 +3992,8 @@
       "sharing/sharing_notification_handler.h",
       "sharing/sharing_ui_controller.cc",
       "sharing/sharing_ui_controller.h",
+      "sharing/sms/sms_remote_fetcher_ui_controller.cc",
+      "sharing/sms/sms_remote_fetcher_ui_controller.h",
       "signin/signin_promo.cc",
       "signin/signin_promo.h",
       "signin/signin_ui_util.cc",