Don't put a text shadow on blue buttons in gtk theme mode.

chrome/browser/ui/libgtk2ui/native_theme_gtk2.cc

Index: chrome/browser/ui/libgtk2ui/native_theme_gtk2.cc
diff --git a/chrome/browser/ui/libgtk2ui/native_theme_gtk2.cc b/chrome/browser/ui/libgtk2ui/native_theme_gtk2.cc
index d4b84fbde18efea0de693db1cb0be8ca35ce2994..41a03ed71eb99fd3a1d1d298ffbe4a4e971cf142 100644
--- a/chrome/browser/ui/libgtk2ui/native_theme_gtk2.cc
+++ b/chrome/browser/ui/libgtk2ui/native_theme_gtk2.cc
@@ -151,6 +151,9 @@ void NativeThemeGtk2::Paint(SkCanvas* canvas,
 }
 
 SkColor NativeThemeGtk2::GetSystemColor(ColorId color_id) const {
+  if (color_id == kColorId_BlueButtonShadowColor)
+    return SK_ColorTRANSPARENT;
+
   return GdkColorToSkColor(GetSystemGdkColor(color_id));
 }
 
@@ -270,6 +273,10 @@ GdkColor NativeThemeGtk2::GetSystemGdkColor(ColorId color_id) const {
       return GetButtonStyle()->bg[GTK_STATE_PRELIGHT];
     case kColorId_BlueButtonPressedColor:
       return GetButtonStyle()->text[GTK_STATE_ACTIVE];
+    case kColorId_BlueButtonShadowColor:
+      // Should be handled in GetSystemColor().
+      NOTREACHED();
+      return GetButtonStyle()->text[GTK_STATE_NORMAL];
 
     // Textfield
     case kColorId_TextfieldDefaultColor: