Remove legacy SELECT popup code.

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 91 matching lines @@
         return defaultButtonGrayColor;
     }
     if (cssValueId == CSSValueMenu)
         return defaultMenuColor;
     return LayoutTheme::systemColor(cssValueId);
 }
 
 // Use the Windows style sheets to match their metrics.
 String LayoutThemeDefault::extraDefaultStyleSheet()
 {
-    String legacyOptionStyle;
-    if (!RuntimeEnabledFeatures::htmlPopupMenuEnabled()) {
-        // Option font must be inherited because we depend on computing the size
-        // of the <select> based on the size of the options, and they must use
-        // the same font for that computation to be correct.
-        legacyOptionStyle = "option { font: inherit !important; }";
-    }
     return LayoutTheme::extraDefaultStyleSheet()
         + loadResourceAsASCIIString("themeWin.css")
         + loadResourceAsASCIIString("themeChromiumSkia.css")
-        + loadResourceAsASCIIString("themeChromium.css")
 #if ENABLE(INPUT_MULTIPLE_FIELDS_UI)
         + loadResourceAsASCIIString("themeInputMultipleFields.css")
 #endif
-        + legacyOptionStyle;
+        + loadResourceAsASCIIString("themeChromium.css");
 }
 
 String LayoutThemeDefault::extraQuirksStyleSheet()
 {
     return loadResourceAsASCIIString("themeWinQuirks.css");
 }
 
 Color LayoutThemeDefault::activeListBoxSelectionBackgroundColor() const
 {
     return Color(0x28, 0x28, 0x28);
@@ skipping 298 matching lines @@
 {
     return progressAnimationInterval;
 }
 
 double LayoutThemeDefault::animationDurationForProgressBar() const
 {
     return progressAnimationInterval * progressAnimationFrames * 2; // "2" for back and forth
 }
 
 } // namespace blink