Add a contentDescription to splitscreen's first staged task

Currently, when we stage the first app in a split, the floatingTaskView has no contentDescription and is announced by screen readers as "unlabeled".

This CL allows FloatingTaskView to copy a contentDescription from the underlying task or ItemInfo when it is created.

Also changes SplitConfigurationOptions#itemInfo to a private field with a public getter for mockito compatibility.

Fixes: 319783133
Test: Confirmed with TalkBack on Overview, contextual and Intent splits
Flag: EXEMPT bugfix
Change-Id: Ia5a95e403bfe8623e17d2ceac9073ef15c7bb476

quickstep/src/com/android/launcher3/uioverrides/QuickstepLauncher.java

@@ -729,7 +729,7 @@ public class QuickstepLauncher extends Launcher implements RecentsViewContainer,
         // Check if there is already an instance of this app running, if so, initiate the split
         // using that.
         mSplitSelectStateController.findLastActiveTasksAndRunCallback(
-                Collections.singletonList(splitSelectSource.itemInfo.getComponentKey()),
+                Collections.singletonList(splitSelectSource.getItemInfo().getComponentKey()),
                 false /* findExactPairMatch */,
                 foundTasks -> {
                     @Nullable Task foundTask = foundTasks[0];
@@ -756,7 +756,7 @@ public class QuickstepLauncher extends Launcher implements RecentsViewContainer,
         Rect tempRect = new Rect();
 
         mSplitSelectStateController.setInitialTaskSelect(source.intent,
-                source.position.stagePosition, source.itemInfo, source.splitEvent,
+                source.position.stagePosition, source.getItemInfo(), source.splitEvent,
                 source.alreadyRunningTaskId);
 
         RecentsView recentsView = getOverviewPanel();
@@ -774,6 +774,8 @@ public class QuickstepLauncher extends Launcher implements RecentsViewContainer,
         floatingTaskView.setOnClickListener(view ->
                 mSplitSelectStateController.getSplitAnimationController().
                         playAnimPlaceholderToFullscreen(this, view, Optional.empty()));
+        floatingTaskView.setContentDescription(source.getItemInfo().contentDescription);
+
         mSplitSelectStateController.setFirstFloatingTaskView(floatingTaskView);
         anim.addListener(new AnimatorListenerAdapter() {
             @Override