Utilize StateListDrawable for key preview background

Change-Id: I268550a185701caecefc27ebaec40fb2c940d883
diff --git a/java/res/values/attrs.xml b/java/res/values/attrs.xml
index c8f6435..05c53a4 100644
--- a/java/res/values/attrs.xml
+++ b/java/res/values/attrs.xml
@@ -54,12 +54,10 @@
 
         <!-- Layout resource for key press feedback.-->
         <attr name="keyPreviewLayout" format="reference" />
-        <!-- The background for key press feedback. -->
-        <attr name="keyPreviewBackground" format="reference" />
-        <!-- The background for the left edge key press feedback. -->
-        <attr name="keyPreviewLeftBackground" format="reference" />
-        <!-- The background for the right edge key press feedback. -->
-        <attr name="keyPreviewRightBackground" format="reference" />
+        <!-- Key preview background states -->
+        <attr name="state_left_edge" format="boolean" />
+        <attr name="state_right_edge" format="boolean" />
+        <attr name="state_has_morekeys" format="boolean" />
         <!-- Vertical offset of the key press feedback from the key. -->
         <attr name="keyPreviewOffset" format="dimension" />
         <!-- Height of the key press feedback popup. -->
diff --git a/java/res/values/styles.xml b/java/res/values/styles.xml
index 634b32a..40f1ff3 100644
--- a/java/res/values/styles.xml
+++ b/java/res/values/styles.xml
@@ -54,9 +54,6 @@
         <item name="keyPopupHintLetterPadding">@dimen/key_popup_hint_letter_padding</item>
         <item name="keyShiftedLetterHintPadding">@dimen/key_uppercase_letter_padding</item>
         <item name="keyPreviewLayout">@layout/key_preview</item>
-        <item name="keyPreviewBackground">@drawable/keyboard_key_feedback</item>
-        <item name="keyPreviewLeftBackground">@null</item>
-        <item name="keyPreviewRightBackground">@null</item>
         <item name="keyPreviewTextColor">#FFFFFFFF</item>
         <item name="keyPreviewOffset">@dimen/key_preview_offset</item>
         <item name="keyPreviewHeight">@dimen/key_preview_height</item>
@@ -323,9 +320,7 @@
         <item name="keyHintLabelColor">#A0FFFFFF</item>
         <item name="keyShiftedLetterHintInactivatedColor">#66E0E4E5</item>
         <item name="keyShiftedLetterHintActivatedColor">#FFFFFFFF</item>
-        <item name="keyPreviewBackground">@drawable/keyboard_key_feedback_ics</item>
-        <item name="keyPreviewLeftBackground">@drawable/keyboard_key_feedback_left_ics</item>
-        <item name="keyPreviewRightBackground">@drawable/keyboard_key_feedback_right_ics</item>
+        <item name="keyPreviewLayout">@layout/key_preview_ics</item>
         <item name="keyPreviewTextColor">#FFFFFFFF</item>
         <item name="keyPreviewOffset">@dimen/key_preview_offset_ics</item>
         <item name="keyTextShadowColor">#00000000</item>