Added isDockable field to RunningTaskInfo

Allows the caller to know if the task can go in the docked stack.

Bug: 26774816
Change-Id: I96fdf9b4df0ac87d84492e1504baac3ca0767d37
diff --git a/services/core/java/com/android/server/am/ActivityStack.java b/services/core/java/com/android/server/am/ActivityStack.java
index b9b2bb6..7de254e 100644
--- a/services/core/java/com/android/server/am/ActivityStack.java
+++ b/services/core/java/com/android/server/am/ActivityStack.java
@@ -4542,6 +4542,7 @@
             }
             ci.numActivities = numActivities;
             ci.numRunning = numRunning;
+            ci.isDockable = task.canGoInDockedStack();
             list.add(ci);
         }
     }