Add external data use observer

chrome/browser/android/datausage/external_data_use_observer.h

Index: chrome/browser/android/datausage/external_data_use_observer.h
diff --git a/chrome/browser/android/datausage/external_data_use_observer.h b/chrome/browser/android/datausage/external_data_use_observer.h
new file mode 100644
index 0000000000000000000000000000000000000000..1199ec868850b5970a36844bbf8e43003fc3960c
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+++ b/chrome/browser/android/datausage/external_data_use_observer.h
@@ -0,0 +1,84 @@
+// 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 CHROME_BROWSER_ANDROID_DATAUSAGE_EXTERNAL_DATA_USE_OBSERVER_H_
+#define CHROME_BROWSER_ANDROID_DATAUSAGE_EXTERNAL_DATA_USE_OBSERVER_H_
+
+#include <jni.h>
+#include <string>
+#include <vector>
+
+#include "base/android/scoped_java_ref.h"
+#include "base/gtest_prod_util.h"
+#include "base/macros.h"
+#include "base/memory/scoped_vector.h"
+#include "base/threading/thread_checker.h"
+#include "components/data_usage/core/data_use.h"
+#include "components/data_usage/core/data_use_aggregator.h"
+
+namespace re2 {
+class RE2;
+}
+
+namespace chrome {
+
+namespace android {
+
+// This class allows platform APIs that are external to Chromium to observe how
+// much data is used by Chromium on the current Android device. It creates and
+// owns a Java listener object that is notified of the data usage observations
+// of Chromium. This class receives regular expressions from the Java listener
+// object. It also registers as a data use observer with DataUseAggregator,
+// filters the received observations by applying the regex matching to the URLs
+// of the requests, and notifies the filtered data use to the Java listener. The
+// Java object in turn may notify the platform APIs of the data usage
+// observations.
+class ExternalDataUseObserver : public data_usage::DataUseAggregator::Observer {
+ public:
+  explicit ExternalDataUseObserver(
+      data_usage::DataUseAggregator* data_use_aggregator);
+  ~ExternalDataUseObserver() override;
+
+ private:
+  FRIEND_TEST_ALL_PREFIXES(ExternalDataUseObserverTest, SingleRegex);
+  FRIEND_TEST_ALL_PREFIXES(ExternalDataUseObserverTest, TwoRegex);
+  FRIEND_TEST_ALL_PREFIXES(ExternalDataUseObserverTest, MultipleRegex);
+  FRIEND_TEST_ALL_PREFIXES(ExternalDataUseObserverTest, ChangeRegex);
+
+  // data_usage::DataUseAggregator::Observer implementation:
+  void OnDataUse(
+      const std::vector<data_usage::DataUse>& data_use_sequence) override;
+
+  // Called by |j_external_data_use_observer_| to register multiple
+  // case-insensitive regular expressions. If the url of the data use request
+  // matches any of the regular expression, the observation is passed to the
+  // Java listener.
+  void RegisterURLRegexes(const std::vector<std::string>& url_regexes);
+
+  // Returns true if the |gurl| matches the registered regular expressions.
+  bool Matches(const GURL& gurl) const;
+
+  // Aggregator that sends data use observations.
+  data_usage::DataUseAggregator* data_use_aggregator_;
+
+  // Java listener that provides regular expressions to this class. The
+  // regular expressions are applied to the request URLs, and filtered
+  // data use is notified to |j_external_data_use_observer_|.
+  base::android::ScopedJavaGlobalRef<jobject> j_external_data_use_observer_;
+
+  // Registered RE2 patterns that are matched against the URLs.
+  ScopedVector<re2::RE2> url_patterns_;
+
+  base::ThreadChecker thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(ExternalDataUseObserver);
+};
+
+bool RegisterExternalDataUseObserver(JNIEnv* env);
+
+}  // namespace android
+
+}  // namespace chrome
+
+#endif  // CHROME_BROWSER_ANDROID_DATAUSAGE_EXTERNAL_DATA_USE_OBSERVER_H_