Revert of Reland 2:Geolocation: move from content/browser to device/

content/browser/geolocation/wifi_data_provider.h

Index: content/browser/geolocation/wifi_data_provider.h
diff --git a/content/browser/geolocation/wifi_data_provider.h b/content/browser/geolocation/wifi_data_provider.h
new file mode 100644
index 0000000000000000000000000000000000000000..ce514969d558d8424798ae71667d95e042fd4c23
--- /dev/null
+++ b/content/browser/geolocation/wifi_data_provider.h
@@ -0,0 +1,74 @@
+// 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 CONTENT_BROWSER_GEOLOCATION_WIFI_DATA_PROVIDER_H_
+#define CONTENT_BROWSER_GEOLOCATION_WIFI_DATA_PROVIDER_H_
+
+#include <set>
+
+#include "base/callback_forward.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/single_thread_task_runner.h"
+#include "content/browser/geolocation/wifi_data.h"
+#include "content/common/content_export.h"
+
+namespace content {
+
+class CONTENT_EXPORT WifiDataProvider
+    : public base::RefCountedThreadSafe<WifiDataProvider> {
+ public:
+  WifiDataProvider();
+
+  // Tells the provider to start looking for data. Callbacks will start
+  // receiving notifications after this call.
+  virtual void StartDataProvider() = 0;
+
+  // Tells the provider to stop looking for data. Callbacks will stop
+  // receiving notifications after this call.
+  virtual void StopDataProvider() = 0;
+
+  // Provides whatever data the provider has, which may be nothing. Return
+  // value indicates whether this is all the data the provider could ever
+  // obtain.
+  virtual bool GetData(WifiData* data) = 0;
+
+  typedef base::Closure WifiDataUpdateCallback;
+
+  void AddCallback(WifiDataUpdateCallback* callback);
+
+  bool RemoveCallback(WifiDataUpdateCallback* callback);
+
+  bool has_callbacks() const;
+
+ protected:
+  friend class base::RefCountedThreadSafe<WifiDataProvider>;
+  virtual ~WifiDataProvider();
+
+  typedef std::set<WifiDataUpdateCallback*> CallbackSet;
+
+  // Runs all callbacks via a posted task, so we can unwind callstack here and
+  // avoid client reentrancy.
+  void RunCallbacks();
+
+  bool CalledOnClientThread() const;
+
+  scoped_refptr<base::SingleThreadTaskRunner> client_task_runner() const {
+    return client_task_runner_;
+  }
+
+ private:
+  void DoRunCallbacks();
+
+  // The task runner for the client thread, all callbacks should run on it.
+  scoped_refptr<base::SingleThreadTaskRunner> client_task_runner_;
+
+  CallbackSet callbacks_;
+
+  DISALLOW_COPY_AND_ASSIGN(WifiDataProvider);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_GEOLOCATION_WIFI_DATA_PROVIDER_H_