Consolidate javascript_dialog_manager.h and javascript_dialog_manager_impl.h

components/app_modal_dialogs/native_app_modal_dialog.h

Index: components/app_modal_dialogs/native_app_modal_dialog.h
diff --git a/components/app_modal_dialogs/native_app_modal_dialog.h b/components/app_modal_dialogs/native_app_modal_dialog.h
index 0d46659beb6da493036700ec17483e4dcc9ab038..7e046accfc198c3418672d56f38c5c60d6df4946 100644
--- a/components/app_modal_dialogs/native_app_modal_dialog.h
+++ b/components/app_modal_dialogs/native_app_modal_dialog.h
@@ -7,6 +7,8 @@
 
 #include "ui/gfx/native_widget_types.h"
 
+namespace app_modal_dialogs {
+
 class JavaScriptAppModalDialog;
 
 class NativeAppModalDialog {
@@ -29,4 +31,6 @@ class NativeAppModalDialog {
   virtual void CancelAppModalDialog() = 0;
 };
 
+}  // namespace app_modal_dialogs
+
 #endif  // COMPONENTS_APP_MODAL_DIALOGS_NATIVE_APP_MODAL_DIALOG_H_