From 838ba119761fb28ee72fb348f532906455214685 Mon Sep 17 00:00:00 2001
From: Wale Ogunwale <ogunwale@google.com>
Date: Thu, 8 Oct 2015 20:18:14 -0700
Subject: [PATCH] Only request traversals if status bar visibility changed on
 reevaluation

Reduces the amount of churn in the system.

Change-Id: Ic1e93f1ed511fe95c551c08a06e239f0e5de93a0
---
 .../com/android/server/wm/WindowManagerService.java    | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/services/core/java/com/android/server/wm/WindowManagerService.java b/services/core/java/com/android/server/wm/WindowManagerService.java
index 6239d2e4aafbf..0170bb9655408 100644
--- a/services/core/java/com/android/server/wm/WindowManagerService.java
+++ b/services/core/java/com/android/server/wm/WindowManagerService.java
@@ -9140,9 +9140,9 @@ public class WindowManagerService extends IWindowManager.Stub
     }
 
     // TOOD(multidisplay): StatusBar on multiple screens?
-    void updateStatusBarVisibilityLocked(int visibility) {
+    boolean updateStatusBarVisibilityLocked(int visibility) {
         if (mLastDispatchedSystemUiVisibility == visibility) {
-            return;
+            return false;
         }
         final int globalDiff = (visibility ^ mLastDispatchedSystemUiVisibility)
                 // We are only interested in differences of one of the
@@ -9173,14 +9173,16 @@ public class WindowManagerService extends IWindowManager.Stub
                 // so sorry
             }
         }
+        return true;
     }
 
     @Override
     public void reevaluateStatusBarVisibility() {
         synchronized (mWindowMap) {
             int visibility = mPolicy.adjustSystemUiVisibilityLw(mLastStatusBarVisibility);
-            updateStatusBarVisibilityLocked(visibility);
-            mWindowPlacerLocked.requestTraversal();
+            if (updateStatusBarVisibilityLocked(visibility)) {
+                mWindowPlacerLocked.requestTraversal();
+            }
         }
     }