Bug 1732738 - Enable display status handling of window occlusion on Windows r=nical,gfx-reviewers

pref handling is removed from WinWindowOcclusionTrackerInteractiveTest. Instead, WinWindowOcclusionTracker::EnsureDisplayStatusObserver() and WinWindowOcclusionTracker::EnsureSessionChangeObserver() are added.

Differential Revision: https://phabricator.services.mozilla.com/D133601

modules/libpref/init/StaticPrefList.yaml

@@ -12610,7 +12610,7 @@
 
 - name: widget.windows.window_occlusion_tracking_display_state.enabled
   type: bool
-  value: false
+  value: true
   mirror: always
 
 - name: widget.windows.window_occlusion_tracking_session_lock.enabled

widget/tests/gtest/TestWinWindowOcclusionTrackerInteractive.cpp

@@ -33,21 +33,16 @@ class WinWindowOcclusionTrackerInteractiveTest : public ::testing::Test {
     }
     EXPECT_EQ(nullptr, WinWindowOcclusionTracker::Get());
 
-    mOldPrefDisplayStatus = Preferences::GetBool(PREF_DISPLAY_STATE);
-    Preferences::SetBool(PREF_DISPLAY_STATE, true);
-    mOldPrefSessionLock = Preferences::GetBool(PREF_SESSION_LOCK);
-    Preferences::SetBool(PREF_SESSION_LOCK, true);
-
     WinWindowOcclusionTracker::Ensure();
     EXPECT_NE(nullptr, WinWindowOcclusionTracker::Get());
+
+    WinWindowOcclusionTracker::Get()->EnsureDisplayStatusObserver();
+    WinWindowOcclusionTracker::Get()->EnsureSessionChangeObserver();
   }
 
   void TearDown() override {
     WinWindowOcclusionTracker::ShutDown();
     EXPECT_EQ(nullptr, WinWindowOcclusionTracker::Get());
-
-    Preferences::SetBool(PREF_DISPLAY_STATE, mOldPrefDisplayStatus);
-    Preferences::SetBool(PREF_SESSION_LOCK, mOldPrefSessionLock);
   }
 
   void SetNativeWindowBounds(HWND aHWnd, const LayoutDeviceIntRect aBounds) {
@@ -120,8 +115,6 @@ class WinWindowOcclusionTrackerInteractiveTest : public ::testing::Test {
     WinWindowOcclusionTracker::Get()->OnDisplayStateChanged(aDisplayOn);
   }
 
-  bool mOldPrefDisplayStatus = false;
-  bool mOldPrefSessionLock = false;
   RefPtr<MockWinWidget> mMockWinWidget;
 };
 

widget/windows/WinEventObserver.cpp

@@ -12,7 +12,6 @@
 
 #include "mozilla/ClearOnShutdown.h"
 #include "mozilla/Logging.h"
-#include "mozilla/StaticPrefs_widget.h"
 #include "mozilla/StaticPtr.h"
 #include "nsHashtablesFwd.h"
 
@@ -121,11 +120,6 @@ void WinEventObserver::Destroy() {
 // static
 already_AddRefed<DisplayStatusObserver> DisplayStatusObserver::Create(
     DisplayStatusListener* aListener) {
-  if (!StaticPrefs::
-          widget_windows_window_occlusion_tracking_display_state_enabled()) {
-    return nullptr;
-  }
-
   WinEventHub::Ensure();
   RefPtr<DisplayStatusObserver> observer = new DisplayStatusObserver(aListener);
   WinEventHub::Get()->AddObserver(observer);
@@ -172,11 +166,6 @@ void DisplayStatusObserver::OnWinEventProc(HWND aHwnd, UINT aMsg,
 // static
 already_AddRefed<SessionChangeObserver> SessionChangeObserver::Create(
     SessionChangeListener* aListener) {
-  if (!StaticPrefs::
-          widget_windows_window_occlusion_tracking_session_lock_enabled()) {
-    return nullptr;
-  }
-
   WinEventHub::Ensure();
   RefPtr<SessionChangeObserver> observer = new SessionChangeObserver(aListener);
   WinEventHub::Get()->AddObserver(observer);

widget/windows/WinWindowOcclusionTracker.cpp

@@ -372,6 +372,20 @@ bool WinWindowOcclusionTracker::IsInWinWindowOcclusionThread() {
          sTracker->mThread->thread_id() == PlatformThread::CurrentId();
 }
 
+void WinWindowOcclusionTracker::EnsureDisplayStatusObserver() {
+  if (mDisplayStatusObserver) {
+    return;
+  }
+  mDisplayStatusObserver = DisplayStatusObserver::Create(this);
+}
+
+void WinWindowOcclusionTracker::EnsureSessionChangeObserver() {
+  if (mSessionChangeObserver) {
+    return;
+  }
+  mSessionChangeObserver = SessionChangeObserver::Create(this);
+}
+
 void WinWindowOcclusionTracker::Enable(nsBaseWidget* aWindow, HWND aHwnd) {
   MOZ_ASSERT(NS_IsMainThread());
   LOG(LogLevel::Info, "WinWindowOcclusionTracker::Enable() aWindow %p aHwnd %p",
@@ -432,8 +446,14 @@ WinWindowOcclusionTracker::WinWindowOcclusionTracker(base::Thread* aThread)
   MOZ_ASSERT(NS_IsMainThread());
   LOG(LogLevel::Info, "WinWindowOcclusionTracker::WinWindowOcclusionTracker()");
 
-  mDisplayStatusObserver = DisplayStatusObserver::Create(this);
-  mSessionChangeObserver = SessionChangeObserver::Create(this);
+  if (StaticPrefs::
+          widget_windows_window_occlusion_tracking_display_state_enabled()) {
+    mDisplayStatusObserver = DisplayStatusObserver::Create(this);
+  }
+  if (StaticPrefs::
+          widget_windows_window_occlusion_tracking_session_lock_enabled()) {
+    mSessionChangeObserver = SessionChangeObserver::Create(this);
+  }
   mSerializedTaskDispatcher = new SerializedTaskDispatcher();
 }
 

widget/windows/WinWindowOcclusionTracker.h

@@ -60,6 +60,12 @@ class WinWindowOcclusionTracker final : public DisplayStatusListener,
   /// Can be called from any thread.
   static bool IsInWinWindowOcclusionThread();
 
+  /// Can only be called from the main thread.
+  void EnsureDisplayStatusObserver();
+
+  /// Can only be called from the main thread.
+  void EnsureSessionChangeObserver();
+
   // Enables notifying to widget via NotifyOcclusionState() when the occlusion
   // state has been computed.
   void Enable(nsBaseWidget* aWindow, HWND aHwnd);