components: Create web_modal component.

chrome/browser/ui/gtk/extensions/native_app_window_gtk.cc

Index: chrome/browser/ui/gtk/extensions/native_app_window_gtk.cc
diff --git a/chrome/browser/ui/gtk/extensions/native_app_window_gtk.cc b/chrome/browser/ui/gtk/extensions/native_app_window_gtk.cc
index 6e3a488f10c2dd4274e49c060caea5c5be9ca6b4..0bd31e345d0d902991a7c741dfef2736b8e0ffc5 100644
--- a/chrome/browser/ui/gtk/extensions/native_app_window_gtk.cc
+++ b/chrome/browser/ui/gtk/extensions/native_app_window_gtk.cc
@@ -302,12 +302,12 @@ gfx::Point NativeAppWindowGtk::GetDialogPosition(const gfx::Size& size) {
 }
 
 void NativeAppWindowGtk::AddObserver(
-    WebContentsModalDialogHostObserver* observer) {
+    web_modal::WebContentsModalDialogHostObserver* observer) {
   observer_list_.AddObserver(observer);
 }
 
 void NativeAppWindowGtk::RemoveObserver(
-    WebContentsModalDialogHostObserver* observer) {
+    web_modal::WebContentsModalDialogHostObserver* observer) {
   observer_list_.RemoveObserver(observer);
 }
 
@@ -361,7 +361,7 @@ void NativeAppWindowGtk::OnDebouncedBoundsChanged() {
   gtk_window_util::UpdateWindowPosition(this, &bounds_, &restored_bounds_);
   shell_window_->OnNativeWindowChanged();
 
-  FOR_EACH_OBSERVER(WebContentsModalDialogHostObserver,
+  FOR_EACH_OBSERVER(web_modal::WebContentsModalDialogHostObserver,
                     observer_list_,
                     OnPositionRequiresUpdate());
 }