Bug 703133: Flush layout data asynchronously on charset changes. r=bz

layout/base/nsPresContext.cpp

@@ -119,6 +119,31 @@
 using namespace mozilla;
 using namespace mozilla::dom;
 
+namespace {
+
+class CharSetChangingRunnable : public nsRunnable
+{
+public:
+  CharSetChangingRunnable(nsPresContext* aPresContext,
+                          const nsCString& aCharSet)
+    : mPresContext(aPresContext),
+      mCharSet(aCharSet)
+  {
+  }
+
+  NS_IMETHOD Run()
+  {
+    mPresContext->DoChangeCharSet(mCharSet);
+    return NS_OK;
+  }
+
+private:
+  nsRefPtr<nsPresContext> mPresContext;
+  nsCString mCharSet;
+};
+
+} // anonymous namespace
+
 static nscolor
 MakeColorPref(const nsString& aColor)
 {
@@ -1072,7 +1097,15 @@ nsPresContext::DestroyImageLoaders()
 }
 
 void
-nsPresContext::UpdateCharSet(const nsAFlatCString& aCharSet)
+nsPresContext::DoChangeCharSet(const nsCString& aCharSet)
+{
+  UpdateCharSet(aCharSet);
+  mDeviceContext->FlushFontCache();
+  RebuildAllStyleData(NS_STYLE_HINT_REFLOW);
+}
+
+void
+nsPresContext::UpdateCharSet(const nsCString& aCharSet)
 {
   if (mLangService) {
     NS_IF_RELEASE(mLanguage);
@@ -1112,10 +1145,9 @@ nsPresContext::Observe(nsISupports* aSubject,
                         const PRUnichar* aData)
 {
   if (!nsCRT::strcmp(aTopic, "charset")) {
-    UpdateCharSet(NS_LossyConvertUTF16toASCII(aData));
-    mDeviceContext->FlushFontCache();
-    RebuildAllStyleData(NS_STYLE_HINT_REFLOW);
-    return NS_OK;
+    nsRefPtr<CharSetChangingRunnable> runnable =
+      new CharSetChangingRunnable(this, NS_LossyConvertUTF16toASCII(aData));
+    return NS_DispatchToCurrentThread(runnable);
   }
 
   NS_WARNING("unrecognized topic in nsPresContext::Observe");

layout/base/nsPresContext.h

@@ -1009,8 +1009,12 @@ protected:
   NS_HIDDEN_(void) GetUserPreferences();
   NS_HIDDEN_(void) GetFontPreferences();
 
-  NS_HIDDEN_(void) UpdateCharSet(const nsAFlatCString& aCharSet);
+  NS_HIDDEN_(void) UpdateCharSet(const nsCString& aCharSet);
 
+public:
+  void DoChangeCharSet(const nsCString& aCharSet);
+
+protected:
   void InvalidateThebesLayers();
   void AppUnitsPerDevPixelChanged();