Refactor LauncherAppTransitionManager & polish for new app transitions.

* Add start delay when launcher resumes from all apps or landscape.
* Track the last app transition animator and cancel it before beginning a new one,
  otherwise the animators can conflict with each other.
  ie. Opening an app from all apps and then immediately pressing back to return to
      all apps.
* Use class overrride instead of UiFactory.

Bug: 70220260
Change-Id: I4755d45d820f9d551e443d6c4a148e8789c5bc57
diff --git a/proguard.flags b/proguard.flags
index 987fb6f..b8cade5 100644
--- a/proguard.flags
+++ b/proguard.flags
@@ -97,6 +97,11 @@
 # support jar.
 -keep class android.support.v7.widget.RecyclerView { *; }
 
+# LauncherAppTransitionManager
+-keep class com.android.launcher3.LauncherAppTransitionManagerImpl {
+    public <init>(...);
+}
+
 -keep interface com.android.launcher3.userevent.nano.LauncherLogProto.** {
   *;
 }