Add AshDesktopMediaList and enable Desktop Capture API on Chrome OS.

chrome/browser/ui/views/desktop_media_picker_views.cc

Index: chrome/browser/ui/views/desktop_media_picker_views.cc
diff --git a/chrome/browser/ui/views/desktop_media_picker_views.cc b/chrome/browser/ui/views/desktop_media_picker_views.cc
index 560fad1df8ee9764b22455405b651b118395df7d..07aa7f55b23101360c1783edc1f516afee751a45 100644
--- a/chrome/browser/ui/views/desktop_media_picker_views.cc
+++ b/chrome/browser/ui/views/desktop_media_picker_views.cc
@@ -479,23 +479,29 @@ DesktopMediaPickerDialogView::DesktopMediaPickerDialogView(
   // DesktopMediaList needs to know the ID of the picker window which
   // matches the ID it gets from the OS. Depending on the OS and configuration
   // we get this ID differently.
-  //
-  // TODO(sergeyu): Update this code when Ash-specific window capturer is
-  // implemented. Currently this code will always get native windows ID
-  // which is not what we need in Ash. http://crbug.com/295102
-  content::DesktopMediaID::Id dialog_window_id;
+  content::DesktopMediaID::Id dialog_window_id = 0;
 
 #if defined(OS_WIN)
   dialog_window_id = reinterpret_cast<content::DesktopMediaID::Id>(
       views::HWNDForWidget(GetWidget()));
 #elif defined(USE_AURA)
-  dialog_window_id = static_cast<content::DesktopMediaID::Id>(
-      GetWidget()->GetNativeWindow()->GetDispatcher()->host()->
-          GetAcceleratedWidget());
-#else
+
+#if defined(USE_ASH)
+  if (ash::Shell::HasInstance()) {
+    dialog_window_id = content::DesktopMediaID::RegisterAuraWindow(
+        GetWidget()->GetNativeWindow()).id;
+  } else
+#endif
+  {
+    dialog_window_id = static_cast<content::DesktopMediaID::Id>(
+        GetWidget()->GetNativeWindow()->GetDispatcher()->host()->
+            GetAcceleratedWidget());
+  }
+
+#else  // defined(USE_AURA)
   dialog_window_id = 0;
   NOTIMPLEMENTED();
-#endif
+#endif  // !defined(USE_AURA)
 
   list_view_->StartUpdating(dialog_window_id);