Switch to LayoutThemeMobile when emulating mobile device in DevTools.

third_party/WebKit/Source/core/layout/LayoutThemeDefault.cpp

 /*
  * Copyright (C) 2007 Apple Inc.
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2008 Collabora Ltd.
  * Copyright (C) 2008, 2009 Google Inc.
  * Copyright (C) 2009 Kenneth Rohde Christiansen
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 52 matching lines @@
 }
 
 unsigned LayoutThemeDefault::m_activeSelectionBackgroundColor = 0xff1e90ff;
 unsigned LayoutThemeDefault::m_activeSelectionForegroundColor = Color::black;
 unsigned LayoutThemeDefault::m_inactiveSelectionBackgroundColor = 0xffc8c8c8;
 unsigned LayoutThemeDefault::m_inactiveSelectionForegroundColor = 0xff323232;
 
 double LayoutThemeDefault::m_caretBlinkInterval;
 
 LayoutThemeDefault::LayoutThemeDefault()
+    : LayoutTheme(nullptr)
 {
     m_caretBlinkInterval = LayoutTheme::caretBlinkInterval();
 }
 
 LayoutThemeDefault::~LayoutThemeDefault()
 {
 }
 
 bool LayoutThemeDefault::themeDrawsFocusRing(const ComputedStyle& style) const
 {
@@ skipping 333 matching lines @@
 {
     return progressAnimationInterval;
 }
 
 double LayoutThemeDefault::animationDurationForProgressBar() const
 {
     return progressAnimationInterval * progressAnimationFrames * 2; // "2" for back and forth
 }
 
 } // namespace blink