Move ApplicationThread to aidl.

Bug: 30977067
Test: Existing tests are passing, dump commands still working.
Change-Id: Iecb382e8720dfb1b6b707272497e3793e6995edb
diff --git a/core/java/android/app/ApplicationPackageManager.java b/core/java/android/app/ApplicationPackageManager.java
index 37faa2e..3b3e070 100644
--- a/core/java/android/app/ApplicationPackageManager.java
+++ b/core/java/android/app/ApplicationPackageManager.java
@@ -1381,7 +1381,7 @@
 
     static void handlePackageBroadcast(int cmd, String[] pkgList, boolean hasPkgInfo) {
         boolean immediateGc = false;
-        if (cmd == IApplicationThread.EXTERNAL_STORAGE_UNAVAILABLE) {
+        if (cmd == ApplicationThreadConstants.EXTERNAL_STORAGE_UNAVAILABLE) {
             immediateGc = true;
         }
         if (pkgList != null && (pkgList.length > 0)) {