Add WorkerSettings to expose certain flag values in WorkerGlobalScope

third_party/WebKit/Source/core/workers/WorkerSettings.h

Index: third_party/WebKit/Source/core/workers/WorkerSettings.h
diff --git a/third_party/WebKit/Source/core/workers/WorkerSettings.h b/third_party/WebKit/Source/core/workers/WorkerSettings.h
new file mode 100644
index 0000000000000000000000000000000000000000..8b5a19c64086c01f5c3844e9e44bdd9bf15d4e02
--- /dev/null
+++ b/third_party/WebKit/Source/core/workers/WorkerSettings.h
@@ -0,0 +1,45 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef WorkerSettings_h
+#define WorkerSettings_h
+
+#include "core/CoreExport.h"
+#include "core/dom/ExecutionContext.h"
+#include "core/frame/Settings.h"
+#include "core/workers/WorkerClients.h"
+#include "platform/Supplementable.h"
+#include "platform/heap/Handle.h"
+
+namespace blink {
+
+class CORE_EXPORT WorkerSettings : public GarbageCollectedFinalized<WorkerSettings>, public Supplement<WorkerClients> {
+    USING_GARBAGE_COLLECTED_MIXIN(WorkerSettings);
+    WTF_MAKE_NONCOPYABLE(WorkerSettings);
+
+public:
+    virtual ~WorkerSettings() {}
+    DECLARE_VIRTUAL_TRACE();
+
+    static WorkerSettings* create(Settings*);
+
+    static const char* supplementName();
+    static WorkerSettings* from(ExecutionContext*);
+
+    bool disableReadingFromCanvas() const { return m_disableReadingFromCanvas; }
+
+private:
+    WorkerSettings() {}
+    void copyFlagValuesFromSettings(Settings*);
+    // The settings that are to be copied from main thread to worker thread
+    // These setting's flag values must remain unchanged throughout the document
+    // lifecycle.
+    // We hard-code the flags as there're very few flags at this moment.
+    bool m_disableReadingFromCanvas = false;
+};
+
+CORE_EXPORT void provideWorkerSettingsToWorker(WorkerClients*, WorkerSettings*);
+}
+
+#endif // WorkerSettings_h