Epicenter API for ListPopupWindow

Introduced epicenter API for ListPopupWindow to mirror the same API that we've made for PopupWindow (b/123768589). Also add mutability protection to PopupWindow epicenter rects

Bug: b/124094855

Test: All widgets tests passed. getter / setter tests introduced in
I648c169b67972c80befbeae9c37c2819eaad27d4
Change-Id: I2b79a16039d345c9c8893b815735a2811543cf60

api/current.txt

@@ -56015,6 +56015,7 @@ package android.widget {
     method @Nullable public android.view.View getAnchorView();
     method @StyleRes public int getAnimationStyle();
     method @Nullable public android.graphics.drawable.Drawable getBackground();
+    method @Nullable public android.graphics.Rect getEpicenterBounds();
     method public int getHeight();
     method public int getHorizontalOffset();
     method public int getInputMethodMode();
@@ -56041,6 +56042,7 @@ package android.widget {
     method public void setBackgroundDrawable(@Nullable android.graphics.drawable.Drawable);
     method public void setContentWidth(int);
     method public void setDropDownGravity(int);
+    method public void setEpicenterBounds(@Nullable android.graphics.Rect);
     method public void setHeight(int);
     method public void setHorizontalOffset(int);
     method public void setInputMethodMode(int);

core/java/android/widget/ListPopupWindow.java

@@ -471,11 +471,24 @@ public class ListPopupWindow implements ShowableListMenu {
      * Specifies the anchor-relative bounds of the popup's transition
      * epicenter.
      *
-     * @param bounds anchor-relative bounds
-     * @hide
+     * @param bounds anchor-relative bounds, or {@code null} to use default epicenter
+     *
+     * @see #getEpicenterBounds()
      */
-    public void setEpicenterBounds(Rect bounds) {
-        mEpicenterBounds = bounds;
+    public void setEpicenterBounds(@Nullable Rect bounds) {
+        mEpicenterBounds = bounds != null ? new Rect(bounds) : null;
+    }
+
+    /**
+     * Returns bounds which are used as a popup's epicenter
+     * of the enter and exit transitions.
+     *
+     * @return bounds relative to anchor view, or {@code null} if not set
+     * @see #setEpicenterBounds(Rect)
+     */
+    @Nullable
+    public Rect getEpicenterBounds() {
+        return mEpicenterBounds != null ? new Rect(mEpicenterBounds) : null;
     }
 
     /**

core/java/android/widget/PopupWindow.java

@@ -490,7 +490,7 @@ public class PopupWindow {
      */
     @Nullable
     public Rect getEpicenterBounds() {
-        return mEpicenterBounds;
+        return mEpicenterBounds != null ? new Rect(mEpicenterBounds) : null;
     }
 
     /**
@@ -509,7 +509,7 @@ public class PopupWindow {
      * @see #getEpicenterBounds()
      */
     public void setEpicenterBounds(@Nullable Rect bounds) {
-        mEpicenterBounds = bounds;
+        mEpicenterBounds = bounds != null ? new Rect(bounds) : null;
     }
 
     private Transition getTransition(int resId) {