Reland change for aura tooltips that was revert due to build break:

ui/aura_shell/aura_shell.gyp

 # Copyright (c) 2011 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
 
   'targets': [
@@ skipping 72 matching lines @@
         'shelf_layout_controller.cc',
         'shelf_layout_controller.h',
         'shell.cc',
         'shell.h',
         'shell_accelerator_controller.cc',
         'shell_accelerator_controller.h',
         'shell_accelerator_filter.cc',
         'shell_accelerator_filter.h',
         'shell_delegate.h',
         'shell_factory.h',
+        'shell_tooltip_manager.cc',
+        'shell_tooltip_manager.h',
         'shell_window_ids.h',
         'show_state_controller.h',
         'show_state_controller.cc',
         'stacking_controller.cc',
         'stacking_controller.h',
         'status_area_view.cc',
         'status_area_view.h',
         'toplevel_frame_view.cc',
         'toplevel_frame_view.h',
         'toplevel_layout_manager.cc',
@@ skipping 94 matching lines @@
         'examples/widgets.cc',
         'examples/window_type_launcher.cc',
         'examples/window_type_launcher.h',
         '<(SHARED_INTERMEDIATE_DIR)/ui/gfx/gfx_resources.rc',
         '<(SHARED_INTERMEDIATE_DIR)/ui/ui_resources/ui_resources.rc',
         '<(SHARED_INTERMEDIATE_DIR)/ui/ui_resources_standard/ui_resources_standard.rc',
       ],
     },
   ],
 }