Fix overdraw in FilterShow activity

bug:7634701
Change-Id: I2da3e3fdb1ef853fa1a0340a1697e5a013ee87f2
diff --git a/res/values/styles.xml b/res/values/styles.xml
index c534ad8..df150e1 100644
--- a/res/values/styles.xml
+++ b/res/values/styles.xml
@@ -28,6 +28,10 @@
         <item name="android:colorBackground">@null</item>
         <item name="android:colorBackgroundCacheHint">@null</item>
     </style>
+    <style name="Theme.FilterShow" parent="Theme.Gallery">
+        <item name="android:windowBackground">@null</item>
+        <item name="android:windowContentOverlay">@null</item>
+    </style>
     <style name="Holo.ActionBar" parent="android:Widget.Holo.ActionBar">
         <item name="android:displayOptions">useLogo|showHome</item>
         <item name="android:background">@drawable/actionbar_translucent</item>