Revert of Bind Window focus ability to the ExecutionContext instead of the process.

Source/core/dom/ExecutionContext.h

Index: Source/core/dom/ExecutionContext.h
diff --git a/Source/core/dom/ExecutionContext.h b/Source/core/dom/ExecutionContext.h
index a77fafca67e6b2dfea922fa08727a444b702ae9d..6decfb99508f6db8a091a40f09768bd144d571bd 100644
--- a/Source/core/dom/ExecutionContext.h
+++ b/Source/core/dom/ExecutionContext.h
@@ -133,10 +133,6 @@
     virtual EventTarget* errorEventTarget() = 0;
     virtual EventQueue* eventQueue() const = 0;
 
-    void allowWindowFocus();
-    void consumeWindowFocus();
-    bool isWindowFocusAllowed() const;
-
 protected:
     ExecutionContext();
     virtual ~ExecutionContext();
@@ -181,12 +177,6 @@
     // ExecutionContext's members (notably m_timeouts) is called before they are destructed,
     // m_lifecycleNotifer should be placed *after* such members.
     OwnPtr<ContextLifecycleNotifier> m_lifecycleNotifier;
-
-    // Counter that keeps track of how many window focus calls are allowed for
-    // this ExecutionContext. Callers are expected to call |allowWindowFocus()|
-    // and |consumeWindowFocus()| in order to increment and decrement the
-    // counter.
-    int m_windowFocusTokens;
 };
 
 } // namespace blink