Fix cropped floating gesture candidate window

ui/keyboard/keyboard_controller_proxy.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/keyboard/keyboard_controller_proxy.h"
 
 #include "base/command_line.h"
 #include "base/values.h"
 #include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
@@ skipping 133 matching lines @@
     keyboard_contents_->GetNativeView()->AddObserver(this);
   }
 
   return keyboard_contents_->GetNativeView();
 }
 
 bool KeyboardControllerProxy::HasKeyboardWindow() const {
   return keyboard_contents_;
 }
 
+bool KeyboardControllerProxy::ShouldWindowOverscroll(
+    aura::Window* window) const {
+  return true;
+}
+
 void KeyboardControllerProxy::ShowKeyboardContainer(aura::Window* container) {
   GetKeyboardWindow()->Show();
   container->Show();
 }
 
 void KeyboardControllerProxy::HideKeyboardContainer(aura::Window* container) {
   container->Hide();
   GetKeyboardWindow()->Hide();
 }
 
@@ skipping 59 matching lines @@
   }
 
   shadow_->SetContentBounds(new_bounds);
 }
 
 void KeyboardControllerProxy::OnWindowDestroyed(aura::Window* window) {
   window->RemoveObserver(this);
 }
 
 }  // namespace keyboard