Boost thread priority when holding the WM lock

Test: Take systrace of open app, make sure thead is boosted while
doing stuff in WM
Test: Run WmSlam with and without boosting. Observe an
improvement.
Bug: 36631902
Change-Id: Iadb036f8d12bbf59091466500e82207cf6fa85d5
diff --git a/services/core/java/com/android/server/wm/WindowContainerController.java b/services/core/java/com/android/server/wm/WindowContainerController.java
index 84ffc35..c4a6837 100644
--- a/services/core/java/com/android/server/wm/WindowContainerController.java
+++ b/services/core/java/com/android/server/wm/WindowContainerController.java
@@ -33,7 +33,7 @@
 
     final WindowManagerService mService;
     final RootWindowContainer mRoot;
-    final HashMap<IBinder, WindowState> mWindowMap;
+    final WindowHashMap mWindowMap;
 
     // The window container this controller owns.
     E mContainer;