Fix synchronization for BlurController.mBlurEnabled

Bug: 177523043
Test: atest BlurTests
Change-Id: Ia730c29aa94e7fcbe09c640e891d6e03bda224d6

services/core/java/com/android/server/wm/BlurController.java

@@ -30,8 +30,6 @@ import android.os.RemoteException;
 import android.provider.Settings;
 import android.view.ICrossWindowBlurEnabledListener;
 
-import com.android.internal.annotations.GuardedBy;
-
 /**
  * Keeps track of the different factors that determine whether cross-window blur is enabled
  * or disabled. Also keeps a list of all interested listeners and notifies them when the
@@ -44,8 +42,7 @@ final class BlurController {
     // We don't use the WM global lock, because the BlurController is not involved in window
     // drawing and only receives binder calls that don't need synchronization with the rest of WM
     private final Object mLock = new Object();
-    @GuardedBy("mLock")
-    boolean mBlurEnabled;
+    private volatile boolean mBlurEnabled;
     private boolean mInPowerSaveMode;
     private boolean mBlurDisabledSetting;
 
@@ -87,9 +84,7 @@ final class BlurController {
     boolean registerCrossWindowBlurEnabledListener(ICrossWindowBlurEnabledListener listener) {
         if (listener == null) return false;
         mBlurEnabledListeners.register(listener);
-        synchronized (mLock) {
-            return mBlurEnabled;
-        }
+        return getBlurEnabled();
     }
 
     void unregisterCrossWindowBlurEnabledListener(ICrossWindowBlurEnabledListener listener) {
@@ -97,6 +92,10 @@ final class BlurController {
         mBlurEnabledListeners.unregister(listener);
     }
 
+    boolean getBlurEnabled() {
+        return mBlurEnabled;
+    }
+
     private void updateBlurEnabled() {
         synchronized (mLock) {
             final boolean newEnabled = CROSS_WINDOW_BLUR_SUPPORTED && !mBlurDisabledSetting

services/core/java/com/android/server/wm/WindowManagerService.java

@@ -6280,7 +6280,7 @@ public class WindowManagerService extends IWindowManager.Stub
             }
         });
         pw.print("  mInTouchMode="); pw.println(mInTouchMode);
-        pw.print("  mBlurEnabled="); pw.println(mBlurController.mBlurEnabled);
+        pw.print("  mBlurEnabled="); pw.println(mBlurController.getBlurEnabled());
         pw.print("  mLastDisplayFreezeDuration=");
                 TimeUtils.formatDuration(mLastDisplayFreezeDuration, pw);
                 if ( mLastFinishedFreezeSource != null) {

services/core/java/com/android/server/wm/WindowManagerShellCommand.java

@@ -217,7 +217,7 @@ public class WindowManagerShellCommand extends ShellCommand {
         String arg = getNextArg();
         if (arg == null) {
             pw.println("Blur supported on device: " + CROSS_WINDOW_BLUR_SUPPORTED);
-            pw.println("Blur enabled: " + mInternal.mBlurController.mBlurEnabled);
+            pw.println("Blur enabled: " + mInternal.mBlurController.getBlurEnabled());
             return 0;
         }
 

services/core/java/com/android/server/wm/WindowState.java

@@ -5344,7 +5344,8 @@ class WindowState extends WindowContainer<WindowState> implements WindowManagerP
     }
 
     private boolean shouldDrawBlurBehind() {
-        return (mAttrs.flags & FLAG_BLUR_BEHIND) != 0 && mWmService.mBlurController.mBlurEnabled;
+        return (mAttrs.flags & FLAG_BLUR_BEHIND) != 0
+            && mWmService.mBlurController.getBlurEnabled();
     }
 
     /**