Return ProcessRecord toString() for WindowProcessController

So it works the way developers are used to.

Bug: N/A
Test: prints
Change-Id: I9cc831d8df1816aea611a6500d20ed0a23cb51da
diff --git a/services/core/java/com/android/server/wm/WindowProcessController.java b/services/core/java/com/android/server/wm/WindowProcessController.java
index 4c9788d..484bd8c 100644
--- a/services/core/java/com/android/server/wm/WindowProcessController.java
+++ b/services/core/java/com/android/server/wm/WindowProcessController.java
@@ -898,6 +898,11 @@
         }
     }
 
+    @Override
+    public String toString() {
+        return mOwner.toString();
+    }
+
     public void dump(PrintWriter pw, String prefix) {
         synchronized (mAtm.mGlobalLock) {
             if (mActivities.size() > 0) {