Implement some UI changes.

Including:
- merge end call button with other buttons
- add ripple effect for buttons
- adjust elevation according to material design guide
- add triangle in expanded view
Bug: 67605985
Test: manual
PiperOrigin-RevId: 174253861
Change-Id: I7b5315245a322235efb39a9cda26b8686cc7bbf9
diff --git a/java/com/android/newbubble/NewBubbleInfo.java b/java/com/android/newbubble/NewBubbleInfo.java
index 44232f3..126b300 100644
--- a/java/com/android/newbubble/NewBubbleInfo.java
+++ b/java/com/android/newbubble/NewBubbleInfo.java
@@ -79,7 +79,7 @@
 
     public abstract Drawable getIconDrawable();
 
-    @Nullable
+    @NonNull
     public abstract CharSequence getName();
 
     @NonNull
@@ -108,7 +108,7 @@
 
       public abstract Builder setIconDrawable(Drawable iconDrawable);
 
-      public abstract Builder setName(@Nullable CharSequence name);
+      public abstract Builder setName(@NonNull CharSequence name);
 
       public abstract Builder setIntent(@NonNull PendingIntent intent);