Start window manager refactoring.

Move all of the pieces into a new com.android.server.wm package.

Change-Id: I942b7bcfb84ee0f843f47d58e55ffc5a93c0da94
diff --git a/services/java/com/android/server/SystemServer.java b/services/java/com/android/server/SystemServer.java
index 6a6cc2a..52c47e1 100644
--- a/services/java/com/android/server/SystemServer.java
+++ b/services/java/com/android/server/SystemServer.java
@@ -17,6 +17,7 @@
 package com.android.server;
 
 import com.android.server.am.ActivityManagerService;
+import com.android.server.wm.WindowManagerService;
 import com.android.internal.app.ShutdownThread;
 import com.android.internal.os.BinderInternal;
 import com.android.internal.os.SamplingProfilerIntegration;