[Extensions Bindings] Add ExtensionBindingsSystem interface; hook it up

extensions/renderer/js_extension_bindings_system.h

Index: extensions/renderer/js_extension_bindings_system.h
diff --git a/extensions/renderer/js_extension_bindings_system.h b/extensions/renderer/js_extension_bindings_system.h
new file mode 100644
index 0000000000000000000000000000000000000000..06fe8069aadc98246be4781ed12416db38617eaa
--- /dev/null
+++ b/extensions/renderer/js_extension_bindings_system.h
@@ -0,0 +1,51 @@
+// 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 EXTENSIONS_RENDERER_JS_EXTENSION_BINDINGS_SYSTEM_H_
+#define EXTENSIONS_RENDERER_JS_EXTENSION_BINDINGS_SYSTEM_H_
+
+#include <memory>
+#include <string>
+
+#include "base/macros.h"
+#include "extensions/renderer/extension_bindings_system.h"
+
+namespace extensions {
+class RequestSender;
+class ResourceBundleSourceMap;
+
+// The bindings system using the traditional JS-injection style bindings.
+class JsExtensionBindingsSystem : public ExtensionBindingsSystem {
+ public:
+  JsExtensionBindingsSystem(ResourceBundleSourceMap* source_map,
+                            std::unique_ptr<RequestSender> request_sender);
+  ~JsExtensionBindingsSystem() override;
+
+  // ExtensionBindingsSystem:
+  void DidCreateScriptContext(ScriptContext* context) override;
+  void WillReleaseScriptContext(ScriptContext* context) override;
+  void UpdateBindingsForContext(ScriptContext* context) override;
+  void DispatchEventInContext(const std::string& event_name,
+                              const base::ListValue* event_args,
+                              const base::DictionaryValue* filtering_info,
+                              ScriptContext* context) override;
+  void HandleResponse(int request_id,
+                      bool success,
+                      const base::ListValue& response,
+                      const std::string& error) override;
+  RequestSender* GetRequestSender() override;
+
+ private:
+  void RegisterBinding(const std::string& api_name, ScriptContext* context);
+
+  ResourceBundleSourceMap* source_map_ = nullptr;
+
+  std::unique_ptr<RequestSender> request_sender_;
+
+  DISALLOW_COPY_AND_ASSIGN(JsExtensionBindingsSystem);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_RENDERER_JS_EXTENSION_BINDINGS_SYSTEM_H_