Consolidate javascript_dialog_manager.h and javascript_dialog_manager_impl.h

components/app_modal/javascript_app_modal_dialog.h

Index: components/app_modal/javascript_app_modal_dialog.h
diff --git a/components/app_modal/javascript_app_modal_dialog.h b/components/app_modal/javascript_app_modal_dialog.h
index 3ea6bca29b696c30e9515abb5ba164515d22a4d6..64883e0be20861d72689524f2cd68c02b557e47d 100644
--- a/components/app_modal/javascript_app_modal_dialog.h
+++ b/components/app_modal/javascript_app_modal_dialog.h
@@ -13,6 +13,8 @@
 #include "components/app_modal/app_modal_dialog.h"
 #include "content/public/browser/javascript_dialog_manager.h"
 
+namespace app_modal {
+
 // Extra data for JavaScript dialogs to add Chrome-only features.
 class ChromeJavaScriptDialogExtraData {
  public:
@@ -98,4 +100,6 @@ class JavaScriptAppModalDialog : public AppModalDialog {
   DISALLOW_COPY_AND_ASSIGN(JavaScriptAppModalDialog);
 };
 
+}  // namespace app_modal
+
 #endif  // COMPONENTS_APP_MODAL_JAVASCRIPT_APP_MODAL_DIALOG_H_