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

content/browser/geolocation/wifi_data.cc

Index: content/browser/geolocation/wifi_data.cc
diff --git a/content/browser/geolocation/wifi_data.cc b/content/browser/geolocation/wifi_data.cc
new file mode 100644
index 0000000000000000000000000000000000000000..d82e6f442f0334ac3db46680335e216416423f70
--- /dev/null
+++ b/content/browser/geolocation/wifi_data.cc
@@ -0,0 +1,57 @@
+// 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.
+
+#include "content/browser/geolocation/wifi_data.h"
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <algorithm>
+#include <limits>
+
+#include "base/logging.h"
+
+namespace content {
+
+AccessPointData::AccessPointData()
+    : radio_signal_strength(std::numeric_limits<int32_t>::min()),
+      channel(std::numeric_limits<int32_t>::min()),
+      signal_to_noise(std::numeric_limits<int32_t>::min()) {}
+
+AccessPointData::~AccessPointData() {}
+
+WifiData::WifiData() {}
+
+WifiData::WifiData(const WifiData& other) = default;
+
+WifiData::~WifiData() {}
+
+bool WifiData::DiffersSignificantly(const WifiData& other) const {
+  // More than 4 or 50% of access points added or removed is significant.
+  static const size_t kMinChangedAccessPoints = 4;
+  const size_t min_ap_count =
+      std::min(access_point_data.size(), other.access_point_data.size());
+  const size_t max_ap_count =
+      std::max(access_point_data.size(), other.access_point_data.size());
+  const size_t difference_threadhold = std::min(kMinChangedAccessPoints,
+                                                min_ap_count / 2);
+  if (max_ap_count > min_ap_count + difference_threadhold)
+    return true;
+  // Compute size of intersection of old and new sets.
+  size_t num_common = 0;
+  for (AccessPointDataSet::const_iterator iter = access_point_data.begin();
+       iter != access_point_data.end();
+       iter++) {
+    if (other.access_point_data.find(*iter) !=
+        other.access_point_data.end()) {
+      ++num_common;
+    }
+  }
+  DCHECK(num_common <= min_ap_count);
+
+  // Test how many have changed.
+  return max_ap_count > num_common + difference_threadhold;
+}
+
+}  // namespace content