Implement ComboView for Bookmarks, History and SavedPages

 - Replaces ComboViewActivity for PhoneUi.
 - Lives as part of the BrowserActivity's ViewTree.
 - Avoids construction of ComboViewActivity everytime the bookmarks screen is opened.

Change-Id: Ic7042de731a4cc2107a297c9f7d4356bc2c30f2e
diff --git a/src/com/android/browser/UI.java b/src/com/android/browser/UI.java
index 172509b..1f881b1 100644
--- a/src/com/android/browser/UI.java
+++ b/src/com/android/browser/UI.java
@@ -88,6 +88,8 @@
 
     public void showComboView(ComboViews startingView, Bundle extra);
 
+    public void hideComboView();
+
     public void showCustomView(View view, int requestedOrientation,
             CustomViewCallback callback);
 
@@ -120,6 +122,8 @@
     // returns if the web page is clear of any overlays (not including sub windows)
     public boolean isWebShowing();
 
+    public boolean isComboViewShowing();
+
     public void showWeb(boolean animate);
 
     Bitmap getDefaultVideoPoster();