[OverlayWindow] Add platform-independent window and views implementation.

chrome/browser/ui/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/chromecast_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/split_static_library.gni")
 import("//chrome/common/features.gni")
@@ skipping 798 matching lines @@
       "passwords/passwords_client_ui_delegate.cc",
       "passwords/passwords_client_ui_delegate.h",
       "passwords/passwords_model_delegate.cc",
       "passwords/passwords_model_delegate.h",
       "pdf/adobe_reader_info_win.cc",
       "pdf/adobe_reader_info_win.h",
       "pdf/chrome_pdf_web_contents_helper_client.cc",
       "pdf/chrome_pdf_web_contents_helper_client.h",
       "permission_bubble/chooser_bubble_delegate.cc",
       "permission_bubble/chooser_bubble_delegate.h",
+      "pip/pip_window.h",

[mlamouri (slow - plz ping), 2017/06/05 13:09:33]

Same as below, what about "picture_in_picture/picture_in_picture_window.h"?

FWIW, I don't expect us to have much stuff in that directory as
chrome/browser/ui/ isn't used by Android so it will only implement the desktop
window. The cross-platform implementation will have to be at a different layer.

[apacible, 2017/06/13 07:58:08]

From a previous conversation with pkasting, spelling out picture_in_picture was
considered too wordy.

       "sad_tab.cc",
       "sad_tab.h",
       "sad_tab_helper.cc",
       "sad_tab_helper.h",
       "sad_tab_types.h",
       "scoped_tabbed_browser_displayer.cc",
       "scoped_tabbed_browser_displayer.h",
       "search/instant_controller.cc",
       "search/instant_controller.h",
       "search/search_delegate.cc",
@@ skipping 760 matching lines @@
       "views/payments/validating_textfield.cc",
       "views/payments/validating_textfield.h",
       "views/payments/validation_delegate.cc",
       "views/payments/validation_delegate.h",
       "views/payments/view_stack.cc",
       "views/payments/view_stack.h",
       "views/permission_bubble/chooser_bubble_ui.cc",
       "views/permission_bubble/chooser_bubble_ui.h",
       "views/permission_bubble/permission_prompt_impl.cc",
       "views/permission_bubble/permission_prompt_impl.h",
+      "views/pip/pip_window_views.cc",
+      "views/pip/pip_window_views.h",
       "views/subtle_notification_view.cc",
       "views/subtle_notification_view.h",
       "views/sync/bubble_sync_promo_view.cc",
       "views/sync/bubble_sync_promo_view.h",
       "views/sync/profile_signin_confirmation_dialog_views.cc",
       "views/sync/profile_signin_confirmation_dialog_views.h",
       "views/task_manager_view.cc",
       "views/task_manager_view.h",
       "views/toolbar/toolbar_actions_bar_bubble_views.cc",
       "views/toolbar/toolbar_actions_bar_bubble_views.h",
@@ skipping 1992 matching lines @@
       "test/test_confirm_bubble_model.cc",
       "test/test_confirm_bubble_model.h",
     ]
     deps += [ "//chrome/test:test_support_ui" ]
   }
 
   if (enable_extensions) {
     deps += [ "//extensions/browser" ]
   }
 }