Remove the compile time flag for DATALIST Element.

Source/core/rendering/RenderThemeChromiumSkia.cpp

Index: Source/core/rendering/RenderThemeChromiumSkia.cpp
diff --git a/Source/core/rendering/RenderThemeChromiumSkia.cpp b/Source/core/rendering/RenderThemeChromiumSkia.cpp
index 083f49d761422ef34d24871fcbfa7a72ac75f931..b2cec88d8adfdd1d38f74630996f608068bc666f 100644
--- a/Source/core/rendering/RenderThemeChromiumSkia.cpp
+++ b/Source/core/rendering/RenderThemeChromiumSkia.cpp
@@ -80,9 +80,10 @@ RenderThemeChromiumSkia::~RenderThemeChromiumSkia()
 // Use the Windows style sheets to match their metrics.
 String RenderThemeChromiumSkia::extraDefaultStyleSheet()
 {
-    return String(themeWinUserAgentStyleSheet, sizeof(themeWinUserAgentStyleSheet)) +
-           String(themeChromiumSkiaUserAgentStyleSheet, sizeof(themeChromiumSkiaUserAgentStyleSheet)) +
-           String(themeChromiumUserAgentStyleSheet, sizeof(themeChromiumUserAgentStyleSheet));
+    return RenderTheme::extraDefaultStyleSheet() +
+        String(themeWinUserAgentStyleSheet, sizeof(themeWinUserAgentStyleSheet)) +
+        String(themeChromiumSkiaUserAgentStyleSheet, sizeof(themeChromiumSkiaUserAgentStyleSheet)) +
+        String(themeChromiumUserAgentStyleSheet, sizeof(themeChromiumUserAgentStyleSheet));
 }
 
 String RenderThemeChromiumSkia::extraQuirksStyleSheet()
@@ -460,12 +461,10 @@ bool RenderThemeChromiumSkia::shouldShowPlaceholderWhenFocused() const
     return true;
 }
 
-#if ENABLE(DATALIST_ELEMENT)
 LayoutUnit RenderThemeChromiumSkia::sliderTickSnappingThreshold() const
 {
     return RenderThemeChromiumCommon::sliderTickSnappingThreshold();
 }
-#endif
 
 //
 // Following values are come from default of GTK+