Add BubbleManager to manage bubbles and ChromeBubbleManager for events.

components/bubble/BUILD.gn

+# Copyright 2015 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.
+
+static_library("bubble") {
+  sources = [
+    "bubble_close_reason.h",
+    "bubble_controller.cc",
+    "bubble_controller.h",
+    "bubble_delegate.cc",
+    "bubble_delegate.h",
+    "bubble_manager.cc",
+    "bubble_manager.h",
+    "bubble_ui.h",
+  ]
+
+  deps = [
+    "//ui/gfx",
+    "//content/public/browser",
+  ]
+}
+
+source_set("unit_tests") {
+  testonly = true
+
+  sources = [
+    "bubble_manager_unittest.cc",
+  ]
+
+  deps = [
+    ":bubble",
+    "//testing/gmock",
+    "//testing/gtest",
+  ]
+}