Add BubbleManager to manage bubbles and ChromeBubbleManager for events.

components/bubble/BUILD.gn

Index: components/bubble/BUILD.gn
diff --git a/chromecast/graphics/BUILD.gn b/components/bubble/BUILD.gn
similarity index 51%
copy from chromecast/graphics/BUILD.gn
copy to components/bubble/BUILD.gn
index f07a87154354163b625be19de5dff4c5ca38b7c9..0fb72a4bb123eb1c29254c79dab88e9478a871f6 100644
--- a/chromecast/graphics/BUILD.gn
+++ b/components/bubble/BUILD.gn
@@ -2,15 +2,18 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-source_set("graphics") {
+static_library("bubble") {
   sources = [
-    "cast_screen.cc",
-    "cast_screen.h",
+    "bubble_controller.cc",
+    "bubble_controller.h",
+    "bubble_delegate.cc",
+    "bubble_delegate.h",
+    "bubble_manager.cc",
+    "bubble_manager.h",
+    "bubble_ui.h",
   ]
 
   deps = [
-    "//ui/aura",
     "//ui/gfx",
-    "//ui/gfx/geometry",
   ]
 }