Add an end to end test: virtual keyboard opens on click of text input

ui/keyboard/keyboard_controller.h

Index: ui/keyboard/keyboard_controller.h
diff --git a/ui/keyboard/keyboard_controller.h b/ui/keyboard/keyboard_controller.h
index a8a743697fe668957f07e8ea984590e18af35e6a..7c19116cf9ab8fec69e469f7c1ceea0d5fd8aa22 100644
--- a/ui/keyboard/keyboard_controller.h
+++ b/ui/keyboard/keyboard_controller.h
@@ -64,9 +64,13 @@ class KEYBOARD_EXPORT KeyboardController : public ui::InputMethodObserver,
   ~KeyboardController() override;
 
   // Returns the container for the keyboard, which is owned by
-  // KeyboardController.
+  // KeyboardController. Creates the container if it's not already created.
   aura::Window* GetContainerWindow();
 
+  // Same as GetContainerWindow except that this function doesn't create the
+  // window.
+  aura::Window* GetContainerWindowWithoutCreationForTest();
+
   // Whether the container window for the keyboard has been initialized.
   bool keyboard_container_initialized() const { return container_ != nullptr; }