Improved the messaging transformation

The messaging layout now transforms smoothly between
the different views.

Test: manual, send messages really fast, expand, collapse
Bug: 63708826
Change-Id: I79da4092eb03fb41a1963b566602386b25141192
diff --git a/core/java/com/android/internal/widget/MessagingLinearLayout.java b/core/java/com/android/internal/widget/MessagingLinearLayout.java
index 7a7447a..f33efff 100644
--- a/core/java/com/android/internal/widget/MessagingLinearLayout.java
+++ b/core/java/com/android/internal/widget/MessagingLinearLayout.java
@@ -53,6 +53,7 @@
      * {@link #NOT_MEASURED_BEFORE} if this is the first layout pass.
      */
     private int mLastMeasuredWidth = NOT_MEASURED_BEFORE;
+    private MessagingLayout mMessagingLayout;
 
     public MessagingLinearLayout(Context context, @Nullable AttributeSet attrs) {
         super(context, attrs);
@@ -258,6 +259,14 @@
         mMaxDisplayedLines = numberLines;
     }
 
+    public void setMessagingLayout(MessagingLayout layout) {
+        mMessagingLayout = layout;
+    }
+
+    public MessagingLayout getMessagingLayout() {
+        return mMessagingLayout;
+    }
+
     public interface MessagingChild {
         int MEASURED_NORMAL = 0;
         int MEASURED_SHORTENED = 1;