Introduce the WebState iOS provider interface.

ios/public/provider/web/web_state.h

Index: ios/public/provider/web/web_state.h
diff --git a/ios/public/provider/web/web_state.h b/ios/public/provider/web/web_state.h
new file mode 100644
index 0000000000000000000000000000000000000000..0e47bbe1ea2ba9173eca7c1fe5904a8024e755a6
--- /dev/null
+++ b/ios/public/provider/web/web_state.h
@@ -0,0 +1,23 @@
+// Copyright 2013 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 IOS_PUBLIC_PROVIDER_WEB_WEB_STATE_H_
+#define IOS_PUBLIC_PROVIDER_WEB_WEB_STATE_H_
+
+#include "ios/public/consumer/base/supports_user_data.h"
+
+namespace ios {
+
+// Core interface for interaction with the web.
+class WebState : public ios::SupportsUserData {
+ public:
+  virtual ~WebState() {}
+
+ protected:
+  WebState() {}
+};
+
+}  // namespace ios
+
+#endif  // IOS_PUBLIC_PROVIDER_WEB_WEB_STATE_H_