Fix issue #3089800: adb shell am -W causes ActivityManager crash

Change-Id: I5508afeb523d84e552117f94c8b70e2bae2c33fa
diff --git a/services/java/com/android/server/am/ActivityStack.java b/services/java/com/android/server/am/ActivityStack.java
index 016ddcd..86c7bdf 100644
--- a/services/java/com/android/server/am/ActivityStack.java
+++ b/services/java/com/android/server/am/ActivityStack.java
@@ -2535,7 +2535,7 @@
                     mWaitingActivityLaunched.add(outResult);
                     do {
                         try {
-                            wait();
+                            mService.wait();
                         } catch (InterruptedException e) {
                         }
                     } while (!outResult.timeout && outResult.who == null);
@@ -2551,7 +2551,7 @@
                         mWaitingActivityVisible.add(outResult);
                         do {
                             try {
-                                wait();
+                                mService.wait();
                             } catch (InterruptedException e) {
                             }
                         } while (!outResult.timeout && outResult.who == null);