Revert of Linux Aura: get tooltip background color from theme

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 39bbb48e4da8db5e48345babc3880daf2c5d36e5..7c08b1da6742fca63b39a1a0343eb1333e6a89f1 100644
--- a/chrome/browser/ui/libgtk2ui/native_theme_gtk2.cc
+++ b/chrome/browser/ui/libgtk2ui/native_theme_gtk2.cc
@@ -245,11 +245,7 @@
     case kColorId_TextfieldSelectionBackgroundFocused:
       return GetEntryStyle()->base[GTK_STATE_SELECTED];
 
-    // Tooltips
-    case kColorId_TooltipBackground:
-      return GetWindowStyle()->bg[GTK_STATE_NORMAL];
-
-    // Trees and Tables (implemented on GTK using the same class)
+      // Trees and Tables (implemented on GTK using the same class)
     case kColorId_TableBackground:
     case kColorId_TreeBackground:
       return GetTreeStyle()->bg[GTK_STATE_NORMAL];
@@ -324,6 +320,9 @@
       return GdkAlphaBlend(win_style->text[GTK_STATE_SELECTED],
                            win_style->bg[GTK_STATE_SELECTED], 0x34);
     }
+    default:
+      // Fall through
+      break;
   }
 
   return SkColorToGdkColor(kInvalidColorIdColor);