Bug 1689945 - Update display info when WM_DISPLAYCHANGE happens r=jrmuizel

GfxInfo::RefreshMonitors() could not be called in ScreenHelperWin::RefreshScreens(), since the RefreshScreens() is called within nsAppShell::Init(). Then GfxInfo::RefreshMonitors() is called during WM_DISPLAYCHANGE event handling.

Differential Revision: https://phabricator.services.mozilla.com/D103661

gfx/tests/gtest/TestConfigManager.cpp

@@ -93,6 +93,7 @@ class MockGfxInfo final : public nsIGfxInfo {
                          JS::MutableHandleValue _retval) override {
     return NS_ERROR_NOT_IMPLEMENTED;
   }
+  NS_IMETHOD RefreshMonitors(void) override { return NS_ERROR_NOT_IMPLEMENTED; }
   NS_IMETHOD GetFailures(nsTArray<int32_t>& indices,
                          nsTArray<nsCString>& failures) override {
     return NS_ERROR_NOT_IMPLEMENTED;

widget/GfxInfoBase.cpp

@@ -1473,6 +1473,9 @@ GfxInfoBase::GetMonitors(JSContext* aCx, JS::MutableHandleValue aResult) {
   return NS_OK;
 }
 
+NS_IMETHODIMP
+GfxInfoBase::RefreshMonitors() { return NS_ERROR_NOT_IMPLEMENTED; }
+
 static inline bool SetJSPropertyString(JSContext* aCx,
                                        JS::Handle<JSObject*> aObj,
                                        const char* aProp, const char* aString) {

widget/GfxInfoBase.h

@@ -56,6 +56,7 @@ class GfxInfoBase : public nsIGfxInfo,
 
   NS_IMETHOD GetMonitors(JSContext* cx,
                          JS::MutableHandleValue _retval) override;
+  NS_IMETHOD RefreshMonitors() override;
   NS_IMETHOD GetFailures(nsTArray<int32_t>& indices,
                          nsTArray<nsCString>& failures) override;
   NS_IMETHOD_(void) LogFailure(const nsACString& failure) override;

widget/nsIGfxInfo.idl

@@ -98,6 +98,8 @@ interface nsIGfxInfo : nsISupports
   [implicit_jscontext]
   jsval getMonitors();
 
+  void refreshMonitors();
+
   Array<ACString> getFailures(out Array<long> indices);
 
   [noscript, notxpcom] void logFailure(in ACString failure);

widget/windows/GfxInfo.cpp

@@ -867,36 +867,7 @@ nsresult GfxInfo::Init() {
   }
 
   // Get monitor information
-  for (int deviceIndex = 0;; deviceIndex++) {
+  RefreshMonitors();
-    DISPLAY_DEVICEW device;
-    device.cb = sizeof(device);
-    if (!::EnumDisplayDevicesW(nullptr, deviceIndex, &device, 0)) {
-      break;
-    }
-
-    if (!(device.StateFlags & DISPLAY_DEVICE_ACTIVE)) {
-      continue;
-    }
-
-    DEVMODEW mode;
-    mode.dmSize = sizeof(mode);
-    mode.dmDriverExtra = 0;
-    if (!::EnumDisplaySettingsW(device.DeviceName, ENUM_CURRENT_SETTINGS,
-                                &mode)) {
-      continue;
-    }
-
-    DisplayInfo displayInfo;
-
-    displayInfo.mScreenWidth = mode.dmPelsWidth;
-    displayInfo.mScreenHeight = mode.dmPelsHeight;
-    displayInfo.mRefreshRate = mode.dmDisplayFrequency;
-    displayInfo.mIsPseudoDisplay =
-        !!(device.StateFlags & DISPLAY_DEVICE_MIRRORING_DRIVER);
-    displayInfo.mDeviceString = device.DeviceString;
-
-    mDisplayInfo.AppendElement(displayInfo);
-  }
 
   const char* spoofedDriverVersionString =
       PR_GetEnv("MOZ_GFX_SPOOF_DRIVER_VERSION");
@@ -931,6 +902,43 @@ GfxInfo::GetAdapterDescription2(nsAString& aAdapterDescription) {
   return NS_OK;
 }
 
+NS_IMETHODIMP
+GfxInfo::RefreshMonitors() {
+  mDisplayInfo.Clear();
+
+  for (int deviceIndex = 0;; deviceIndex++) {
+    DISPLAY_DEVICEW device;
+    device.cb = sizeof(device);
+    if (!::EnumDisplayDevicesW(nullptr, deviceIndex, &device, 0)) {
+      break;
+    }
+
+    if (!(device.StateFlags & DISPLAY_DEVICE_ACTIVE)) {
+      continue;
+    }
+
+    DEVMODEW mode;
+    mode.dmSize = sizeof(mode);
+    mode.dmDriverExtra = 0;
+    if (!::EnumDisplaySettingsW(device.DeviceName, ENUM_CURRENT_SETTINGS,
+                                &mode)) {
+      continue;
+    }
+
+    DisplayInfo displayInfo;
+
+    displayInfo.mScreenWidth = mode.dmPelsWidth;
+    displayInfo.mScreenHeight = mode.dmPelsHeight;
+    displayInfo.mRefreshRate = mode.dmDisplayFrequency;
+    displayInfo.mIsPseudoDisplay =
+        !!(device.StateFlags & DISPLAY_DEVICE_MIRRORING_DRIVER);
+    displayInfo.mDeviceString = device.DeviceString;
+
+    mDisplayInfo.AppendElement(displayInfo);
+  }
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 GfxInfo::GetAdapterRAM(uint32_t* aAdapterRAM) {
   uint32_t result = 0;

widget/windows/GfxInfo.h

@@ -66,6 +66,8 @@ class GfxInfo : public GfxInfoBase {
 
   nsresult FindMonitors(JSContext* cx, JS::HandleObject array) override;
 
+  NS_IMETHOD RefreshMonitors() override;
+
 #ifdef DEBUG
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_NSIGFXINFODEBUG

widget/windows/nsWindow.cpp

@@ -5967,6 +5967,10 @@ bool nsWindow::ProcessMessage(UINT msg, WPARAM& wParam, LPARAM& lParam,
 
     case WM_DISPLAYCHANGE: {
       ScreenHelperWin::RefreshScreens();
+      nsCOMPtr<nsIGfxInfo> gfxInfo = services::GetGfxInfo();
+      if (gfxInfo) {
+        gfxInfo->RefreshMonitors();
+      }
       if (mWidgetListener) {
         mWidgetListener->UIResolutionChanged();
       }