Switch to LayoutThemeMobile when emulating mobile device in DevTools.

third_party/WebKit/Source/core/paint/ThemePainterDefault.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 115 matching lines @@
     // Move the rect into partLayoutObject's coords.
     partRect.move(offsetFromInputLayoutObject);
     // Account for the local drawing offset.
     partRect.move(localOffset.x(), localOffset.y());
 
     return pixelSnappedIntRect(partRect);
 }
 
 } // namespace
 
+ThemePainterDefault::ThemePainterDefault()
+    : ThemePainter(nullptr)
+{
+}
+
 bool ThemePainterDefault::paintCheckbox(const LayoutObject& o, const PaintInfo& i, const IntRect& rect)
 {
     WebThemeEngine::ExtraParams extraParams;
     WebCanvas* canvas = i.context.canvas();
     extraParams.button.checked = LayoutTheme::isChecked(o);
     extraParams.button.indeterminate = LayoutTheme::isIndeterminate(o);
 
     float zoomLevel = o.styleRef().effectiveZoom();
     GraphicsContextStateSaver stateSaver(i.context, false);
     IntRect unzoomedRect = rect;
@@ skipping 268 matching lines @@
         inputContentBox.y() + (inputContentBox.height() - magnifierSize + 1) / 2,
         magnifierSize, magnifierSize);
     IntRect paintingRect = convertToPaintingRect(inputLayoutBox, magnifierObject, magnifierRect, r);
 
     DEFINE_STATIC_REF(Image, magnifierImage, (Image::loadPlatformResource("searchMagnifier")));
     paintInfo.context.drawImage(magnifierImage, paintingRect);
     return false;
 }
 
 } // namespace blink