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

Source/WebKit/chromium/public/WebSettings.h

Index: Source/WebKit/chromium/public/WebSettings.h
diff --git a/Source/WebKit/chromium/public/WebSettings.h b/Source/WebKit/chromium/public/WebSettings.h
index 3d91c193d59d62cba413a2c9ffb3389f2317fe11..df2509637733b071b12a01ba23c88bc596d7ef4f 100644
--- a/Source/WebKit/chromium/public/WebSettings.h
+++ b/Source/WebKit/chromium/public/WebSettings.h
@@ -52,6 +52,8 @@ public:
         EditingBehaviorAndroid
     };
 
+    virtual void settingsChanged() const = 0;

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

I'm surprised this is a public API.  Is the embedder required to call this
function any time it calls any setters on this object?  If so, why not skip
exposing it as an API and make the setters themselves call it?

[Ken Russell (switch to Gerrit), 2013/05/06 22:12:22]

It's not possible to detect internally when would be a good point to broadcast
the settings changed notifications. Fortunately, there's only one point in the
embedder that needs to call this method.

+
     virtual bool scrollAnimatorEnabled() const = 0;
     virtual bool touchEditingEnabled() const = 0;
     virtual bool viewportEnabled() const = 0;