Lose/restore WebGL contexts if multisampling blackist status changes at runtime.

Source/core/page/Page.h

Index: Source/core/page/Page.h
diff --git a/Source/core/page/Page.h b/Source/core/page/Page.h
index d58734140d43ce0c6dcfb8c065bed6c6cd680450..5467ab41ce520a40f60380af26d837706a9d66da 100644
--- a/Source/core/page/Page.h
+++ b/Source/core/page/Page.h
@@ -259,6 +259,16 @@ public:
 
     double timerAlignmentInterval() const;
 
+    class SettingsChangedObserver {
+    public:
+        virtual void settingsChanged(Settings*) = 0;
+        virtual ~SettingsChangedObserver() {}

[abarth-chromium, 2013/05/06 21:58:30]

Shouldn't this destructor call removeSettingsChangedObserver?  It seems like
every object that subclasses this object will need to make that call in its
destructor to be correct.

Similarly, perhaps the constructor should call addSettingsChangedObserver.

[bajones, 2013/05/06 22:44:14]

Not a bad idea. I'll make sure that's in the next revision.

+    };
+
+    void addSettingsChangedObserver(SettingsChangedObserver*);
+    void removeSettingsChangedObserver(SettingsChangedObserver*);
+    void settingsChanged() const;
+
 private:
     void initGroup();
 
@@ -339,6 +349,8 @@ private:
     AlternativeTextClient* m_alternativeTextClient;
 
     OwnPtr<PageConsole> m_console;
+
+    HashSet<SettingsChangedObserver*> m_settingsChangedObservers;

[abarth-chromium, 2013/05/06 21:58:30]

More raw pointers...  Can this be HashSet<OwnPtr<...> > instead?

 };
 
 } // namespace WebCore