Add GCController support to test_shell....

webkit/port/bindings/v8/ScriptController.h

Index: webkit/port/bindings/v8/ScriptController.h
===================================================================
--- webkit/port/bindings/v8/ScriptController.h	(revision 5396)
+++ webkit/port/bindings/v8/ScriptController.h	(working copy)
@@ -218,6 +218,20 @@
     static bool RecordPlaybackMode() { return m_recordPlaybackMode; }
     static void setRecordPlaybackMode(bool value) { m_recordPlaybackMode = value; }
 
+    // Set/Get ShouldExposeGCController flag.
+    // Some WebKit layout test need window.GCController.collect() to
+    // trigger GC, this flag lets the binding code expose
+    // window.GCController.collect() to the JavaScript code.
+    // 
+    // GCController.collect() needs V8 engine expose gc() function by passing
+    // '--expose-gc' flag to the engine.
+    static bool shouldExposeGCController() {
+        return m_shouldExposeGCController;
+    }
+    static void setShouldExposeGCController(bool value) {
+        m_shouldExposeGCController = value;
+    }
+
     void finishedWithEvent(Event*);
     void setEventHandlerLineno(int lineno);
 
@@ -245,6 +259,7 @@
 
 private:
     static bool m_recordPlaybackMode;
+    static bool m_shouldExposeGCController;
 
     Frame* m_frame;
     const String* m_sourceURL;