[webnfc] Implement nfc.watch in blink nfc module.

third_party/WebKit/Source/modules/nfc/NFC.h

 // Copyright 2015 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 NFC_h
 #define NFC_h
 
 #include "bindings/core/v8/CallbackPromiseAdapter.h"
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "bindings/modules/v8/UnionTypesModules.h"
 #include "core/page/PageLifecycleObserver.h"
 #include "device/nfc/nfc.mojom-wtf.h"
+#include "modules/nfc/MessageCallback.h"
 #include "mojo/public/cpp/bindings/binding.h"
+#include "wtf/HashMap.h"
 
 namespace blink {
 
 class MessageCallback;
 class NFCError;
 class NFCPushOptions;
 using NFCPushMessage = StringOrArrayBufferOrNFCMessage;
+class NFCWatchCallback;
 class NFCWatchOptions;
 class ServiceRegistry;
 
 class NFC final
     : public GarbageCollectedFinalized<NFC>
     , public ScriptWrappable
     , public PageLifecycleObserver
     , WTF_NON_EXPORTED_BASE(public device::wtf::NFCClient)
 {
     DEFINE_WRAPPERTYPEINFO();
@@ skipping 19 matching lines @@
     // Cancels all watch operations.
     ScriptPromise cancelWatch(ScriptState*);
 
     // Implementation of PageLifecycleObserver.
     void pageVisibilityChanged() override;
 
     // Interface required by garbage collection.
     DECLARE_VIRTUAL_TRACE();
 
 private:
+    friend class NFCWatchCallback;
     bool Initialize(ServiceRegistry*);
+
+    // Returns promise with DOMException if feature is not supported
+    // or when context is not secure. Otherwise, returns empty promise.
+    ScriptPromise RejectIfNotSupported(ScriptState*);
     void OnError();
     // device::wtf::NFCClient implementation
     void OnWatch(uint32_t id, device::wtf::NFCMessagePtr) override;
+    void OnWatchRegistered(uint32_t id, MessageCallback*);
 
 private:
     explicit NFC(LocalFrame*);
     device::wtf::NFCPtr m_nfc;
     mojo::Binding<device::wtf::NFCClient> m_client;
+    using WatchCallbacksMap = HeapHashMap<uint32_t, Member<MessageCallback>>;
+    WatchCallbacksMap m_callbacks;
 };
 
 } // namespace blink
 
 #endif // NFC_h