Bug 1400317 - Win32k Lockdown: Remote IsAppThemed() r=jmathies

Differential Revision: https://phabricator.services.mozilla.com/D80566

widget/windows/WinContentSystemParameters.cpp

@@ -25,6 +25,9 @@ struct WinContentSystemParameters::Detail {
   bool cachedIsPerMonitorDPIAware{false};
   float cachedSystemDPI{0.0f};
   bool cachedFlatMenusEnabled{false};
+
+  // Almost-always true in Windows 7, always true starting in Windows 8
+  bool cachedIsAppThemed{true};
 };
 
 // static
@@ -63,6 +66,14 @@ bool WinContentSystemParameters::AreFlatMenusEnabled() {
   return mDetail->cachedFlatMenusEnabled;
 }
 
+bool WinContentSystemParameters::IsAppThemed() {
+  MOZ_ASSERT(XRE_IsContentProcess());
+
+  OffTheBooksMutexAutoLock lock(mDetail->mutex);
+  MOZ_RELEASE_ASSERT(IsCachedValueValid(SystemParameterId::IsAppThemed));
+  return mDetail->cachedIsAppThemed;
+}
+
 void WinContentSystemParameters::SetContentValueInternal(
     const SystemParameterKVPair& aKVPair) {
   MOZ_ASSERT(XRE_IsContentProcess());
@@ -87,6 +98,10 @@ void WinContentSystemParameters::SetContentValueInternal(
       mDetail->cachedFlatMenusEnabled = aKVPair.value();
       return;
 
+    case SystemParameterId::IsAppThemed:
+      mDetail->cachedIsAppThemed = aKVPair.value();
+      return;
+
     case SystemParameterId::Count:
       MOZ_CRASH("Invalid SystemParameterId");
   }
@@ -124,6 +139,10 @@ bool WinContentSystemParameters::GetParentValueInternal(
       aKVPair->value() = nsUXThemeData::AreFlatMenusEnabled();
       return true;
 
+    case SystemParameterId::IsAppThemed:
+      aKVPair->value() = nsUXThemeData::IsAppThemed();
+      return true;
+
     case SystemParameterId::Count:
       MOZ_CRASH("Invalid SystemParameterId");
   }
@@ -154,6 +173,12 @@ void WinContentSystemParameters::OnThemeChanged() {
     updates.AppendElement(std::move(kvPair));
   }
 
+  {
+    dom::SystemParameterKVPair kvPair{};
+    GetParentValueInternal(SystemParameterId::IsAppThemed, &kvPair);
+    updates.AppendElement(std::move(kvPair));
+  }
+
   nsTArray<dom::ContentParent*> contentProcesses{};
   dom::ContentParent::GetAll(contentProcesses);
   for (auto contentProcess : contentProcesses) {

widget/windows/WinContentSystemParameters.h

@@ -22,6 +22,7 @@ enum class SystemParameterId : uint8_t {
   IsPerMonitorDPIAware = 0,
   SystemDPI,
   FlatMenusEnabled,
+  IsAppThemed,
   Count,
 };
 
@@ -35,6 +36,8 @@ class WinContentSystemParameters {
 
   bool AreFlatMenusEnabled();
 
+  bool IsAppThemed();
+
   void SetContentValues(const nsTArray<dom::SystemParameterKVPair>& values);
 
   nsTArray<dom::SystemParameterKVPair> GetParentValues();

widget/windows/nsUXThemeData.cpp

@@ -402,4 +402,9 @@ bool nsUXThemeData::AreFlatMenusEnabled() {
 }
 
 // static
-bool nsUXThemeData::IsAppThemed() { return !!::IsAppThemed(); }
+bool nsUXThemeData::IsAppThemed() {
+  if (XRE_IsContentProcess()) {
+    return WinContentSystemParameters::GetSingleton()->IsAppThemed();
+  }
+  return !!::IsAppThemed();
+}