Replace GcmListener with FirebaseMessagingService

This uses the new firebase_messaging library to receive messages from
FCM and route them to the corresponding handler.

Bug: 1138706
Change-Id: Ic12c37687acfddf036008d12c8794c37ff8da957
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2615700
Reviewed-by: Ben Pastene <bpastene@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Richard Knoll <knollr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#848182}
GitOrigin-RevId: a59edbdba691e190d696eda5aaaea0eccc7d3eea

BUILD.gn

diff --git a/BUILD.gn b/BUILD.gn
index efaba4e..ca571ae 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -63,7 +63,4 @@
     testonly = true
     sources = [ "//third_party/android_sdk/public/extras/chromium/support/src/org/chromium/android/support/PackageManagerWrapper.java" ]
   }
-  android_java_prebuilt("android_gcm_java") {
-    jar_path = "//third_party/android_sdk/public/extras/google/gcm/gcm-client/dist/gcm.jar"
-  }
 }

README.chromium

diff --git a/README.chromium b/README.chromium
index ab66ba5..ef5c34a 100644
--- a/README.chromium
+++ b/README.chromium
@@ -7,7 +7,6 @@
   Android SDK Platform-tools 30.0.3
   Android SDK Platform API 30
   Android SDK Sources 29
-  Google Cloud Messaging 3
   SDK Patch Applier v4
 Security Critical: no
 License: Apache Version 2.0

cipd/extras/google/gcm.yaml

diff --git a/cipd/extras/google/gcm.yaml b/cipd/extras/google/gcm.yaml
deleted file mode 100644
index ae20a19..0000000
--- a/cipd/extras/google/gcm.yaml
+++ /dev/null
@@ -1,13 +0,0 @@
-# Copyright 2019 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-package: chromium/third_party/android_sdk/public/extras/google/gcm
-description: extras Android SDK Extras library
-root: ../../../public/
-data:
-  - dir: extras/google/gcm
-# Some tools inspect their argv0 and don't handle CIPD's symlink structure
-# correctly. Install in copy mode so that they can find the other directories
-# relative to themselves.
-install_mode: copy