Bug 1813573 - Part 2. Restart vsync when refresh rate is changed. r=geckoview-reviewers,owlish

When refresh rate is changed, `DisplayListener` is called. So we restart vsync
when refresh rate may be changed.

Differential Revision: https://phabricator.services.mozilla.com/D168666

gfx/thebes/gfxAndroidPlatform.cpp

@@ -336,6 +336,17 @@ class AndroidVsyncSource final : public VsyncSource,
     NotifyVsync(vsyncTime, outputTime);
   }
 
+  void OnMaybeUpdateRefreshRate() override {
+    NS_DispatchToMainThread(
+        NS_NewRunnableFunction(__func__, [self = RefPtr{this}]() {
+          if (!self->mObservingVsync) {
+            return;
+          }
+          self->DisableVsync();
+          self->EnableVsync();
+        }));
+  }
+
  private:
   virtual ~AndroidVsyncSource() { DisableVsync(); }
 

mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoScreenChangeListener.java

@@ -45,7 +45,12 @@ public class GeckoScreenChangeListener implements DisplayManager.DisplayListener
       return;
     }
 
-    GeckoScreenOrientation.getInstance().update(displayManager.getDisplay(displayId));
+    if (GeckoScreenOrientation.getInstance().update(displayManager.getDisplay(displayId))) {
+      // refreshScreenInfo is already called.
+      return;
+    }
+
+    ScreenManagerHelper.refreshScreenInfo();
   }
 
   private static DisplayManager getDisplayManager() {

widget/android/AndroidVsync.cpp

@@ -130,5 +130,18 @@ void AndroidVsync::NotifyVsync(int64_t aFrameTimeNanos) {
   }
 }
 
+void AndroidVsync::OnMaybeUpdateRefreshRate() {
+  // Do not keep the lock held while calling OnVsync.
+  nsTArray<Observer*> observers;
+  {
+    auto impl = mImpl.Lock();
+    observers.AppendElements(impl->mInputObservers);
+    observers.AppendElements(impl->mRenderObservers);
+  }
+  for (Observer* observer : observers) {
+    observer->OnMaybeUpdateRefreshRate();
+  }
+}
+
 }  // namespace widget
 }  // namespace mozilla

widget/android/AndroidVsync.h

@@ -35,6 +35,8 @@ class AndroidVsync final : public SupportsThreadSafeWeakPtr<AndroidVsync> {
    public:
     // Will be called on the Java UI thread.
     virtual void OnVsync(const TimeStamp& aTimeStamp) = 0;
+    // Will be called on the Java UI thread.
+    virtual void OnMaybeUpdateRefreshRate() {}
     // Called when the observer is unregistered, in case it wants to
     // manage its own lifetime.
     virtual void Dispose() {}
@@ -46,6 +48,8 @@ class AndroidVsync final : public SupportsThreadSafeWeakPtr<AndroidVsync> {
   void RegisterObserver(Observer* aObserver, ObserverType aType);
   void UnregisterObserver(Observer* aObserver, ObserverType aType);
 
+  void OnMaybeUpdateRefreshRate();
+
  private:
   friend class AndroidVsyncSupport;
 

widget/android/ScreenHelperAndroid.cpp

@@ -10,6 +10,7 @@
 
 #include <mozilla/jni/Refs.h>
 
+#include "AndroidVsync.h"
 #include "mozilla/Atomics.h"
 #include "mozilla/java/GeckoAppShellWrappers.h"
 #include "mozilla/java/ScreenManagerHelperNatives.h"
@@ -62,4 +63,8 @@ void ScreenHelperAndroid::Refresh() {
   AutoTArray<RefPtr<Screen>, 1> screens;
   screens.AppendElement(MakePrimaryScreen());
   ScreenManager::Refresh(std::move(screens));
+
+  if (RefPtr<AndroidVsync> vsync = AndroidVsync::GetInstance()) {
+    vsync->OnMaybeUpdateRefreshRate();
+  }
 }