Oilpan: Introduce a state transition model for Oilpan GC states

Source/bindings/core/v8/V8GCController.cpp

Index: Source/bindings/core/v8/V8GCController.cpp
diff --git a/Source/bindings/core/v8/V8GCController.cpp b/Source/bindings/core/v8/V8GCController.cpp
index c0cb293dab115633d1b8c25b552a7ad639154100..37a013439ea1eeb45be00a9b6bc95652fde986b7 100644
--- a/Source/bindings/core/v8/V8GCController.cpp
+++ b/Source/bindings/core/v8/V8GCController.cpp
@@ -451,7 +451,7 @@ void V8GCController::majorGCEpilogue(v8::Isolate* isolate)
         //     the DOM objects are not collected forever. (Note that
         //     Oilpan's GC is not triggered unless Oilpan's heap gets full.)
         // (6) V8 hits OOM.
-        ThreadState::current()->setGCRequested();
+        ThreadState::current()->setGCState(ThreadState::GCScheduled);
     }
 }