Bug 1584319 - refactor the way of requesting wakelock on Windows. r=jmathies

Current implementation would fail to request a non-display wakelock on Windows when we ask for a background audio lock. The check for `audio-playing` with `locked-background` is incorrect. Therefore, adding new a variable to tell if we should request a non-display lock.

Differential Revision: https://phabricator.services.mozilla.com/D60201

--HG--
extra : moz-landing-system : lando

widget/windows/nsAppShell.cpp

@@ -53,40 +53,40 @@ class WinWakeLockListener final : public nsIDOMMozWakeLockListener {
 
   NS_IMETHOD Callback(const nsAString& aTopic,
                       const nsAString& aState) override {
+    WAKE_LOCK_LOG("WinWakeLock: topic=%s, state=%s",
+                  NS_ConvertUTF16toUTF8(aTopic).get(),
+                  NS_ConvertUTF16toUTF8(aState).get());
     if (!aTopic.EqualsASCII("screen") && !aTopic.EqualsASCII("audio-playing") &&
         !aTopic.EqualsASCII("video-playing")) {
       return NS_OK;
     }
 
-    // we should still hold the lock for background audio.
-    if (aTopic.EqualsASCII("audio-playing") &&
-        aState.EqualsASCII("locked-background")) {
-      return NS_OK;
+    // Check what kind of lock we will require, if both display lock and non
+    // display lock are needed, we would require display lock because it has
+    // higher priority.
+    if (aTopic.EqualsASCII("audio-playing")) {
+      mRequireForNonDisplayLock = aState.EqualsASCII("locked-foreground") ||
+                                  aState.EqualsASCII("locked-background");
+    } else if (aTopic.EqualsASCII("screen") ||
+               aTopic.EqualsASCII("video-playing")) {
+      mRequireForDisplayLock = aState.EqualsASCII("locked-foreground");
     }
 
-    if (aTopic.EqualsASCII("screen") || aTopic.EqualsASCII("video-playing")) {
-      mRequireForDisplay = aState.EqualsASCII("locked-foreground");
-    }
-
-    // Note the wake lock code ensures that we're not sent duplicate
-    // "locked-foreground" notifications when multiple wake locks are held.
-    if (aState.EqualsASCII("locked-foreground")) {
-      WAKE_LOCK_LOG("WinWakeLock: Blocking screen saver");
-      if (mRequireForDisplay) {
-        // Prevent the display turning off and block the screen saver.
-        SetThreadExecutionState(ES_DISPLAY_REQUIRED | ES_CONTINUOUS);
-      } else {
-        SetThreadExecutionState(ES_SYSTEM_REQUIRED | ES_CONTINUOUS);
-      }
+    if (mRequireForDisplayLock) {
+      WAKE_LOCK_LOG("WinWakeLock: Request display lock");
+      SetThreadExecutionState(ES_DISPLAY_REQUIRED | ES_CONTINUOUS);
+    } else if (mRequireForNonDisplayLock) {
+      WAKE_LOCK_LOG("WinWakeLock: Request non-display lock");
+      SetThreadExecutionState(ES_SYSTEM_REQUIRED | ES_CONTINUOUS);
     } else {
-      WAKE_LOCK_LOG("WinWakeLock: Unblocking screen saver");
-      // Unblock display/screen saver turning off.
+      WAKE_LOCK_LOG("WinWakeLock: reset lock");
       SetThreadExecutionState(ES_CONTINUOUS);
     }
     return NS_OK;
   }
 
-  bool mRequireForDisplay = false;
+  bool mRequireForDisplayLock = false;
+  bool mRequireForNonDisplayLock = false;
 };
 
 NS_IMPL_ISUPPORTS(WinWakeLockListener, nsIDOMMozWakeLockListener)