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

Source/core/dom/ExecutionContext.cpp

Index: Source/core/dom/ExecutionContext.cpp
diff --git a/Source/core/dom/ExecutionContext.cpp b/Source/core/dom/ExecutionContext.cpp
index 887f2e70ee4a597c20c5fe8596055cf0084bb9fb..240a99d3fe3675b87db24d68d3a251f68b9a4435 100644
--- a/Source/core/dom/ExecutionContext.cpp
+++ b/Source/core/dom/ExecutionContext.cpp
@@ -36,6 +36,7 @@
 #include "core/html/PublicURLManager.h"
 #include "core/inspector/InspectorInstrumentation.h"
 #include "core/inspector/ScriptCallStack.h"
+#include "core/page/WindowFocusAllowedIndicator.h"
 #include "core/workers/WorkerGlobalScope.h"
 #include "core/workers/WorkerThread.h"
 #include "wtf/MainThread.h"
@@ -73,6 +74,7 @@ ExecutionContext::ExecutionContext()
     , m_inDispatchErrorEvent(false)
     , m_activeDOMObjectsAreSuspended(false)
     , m_activeDOMObjectsAreStopped(false)
+    , m_windowFocusTokens(0)
 {
 }
 
@@ -271,6 +273,26 @@ void ExecutionContext::enforceSandboxFlags(SandboxFlags mask)
     }
 }
 
+void ExecutionContext::allowWindowFocus()
+{
+    ++m_windowFocusTokens;
+}
+
+void ExecutionContext::consumeWindowFocus()
+{
+    if (m_windowFocusTokens == 0)
+        return;
+    --m_windowFocusTokens;
+}
+
+bool ExecutionContext::isWindowFocusAllowed() const
+{
+    // FIXME: WindowFocusAllowedIndicator::windowFocusAllowed() is temporary,
+    // it will be removed as soon as WebScopedWindowFocusAllowedIndicator will
+    // be updated to not use WindowFocusAllowedIndicator.
+    return m_windowFocusTokens > 0 || WindowFocusAllowedIndicator::windowFocusAllowed();
+}
+
 void ExecutionContext::trace(Visitor* visitor)
 {
 #if ENABLE(OILPAN)