[TTS] Record CTR by week and 28-day intervals.

chrome/browser/android/contextualsearch/ctr_recorder.h

+// Copyright 2016 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_CONTEXTUALSEARCH_CTR_RECORDER_H_
+#define CHROME_BROWSER_ANDROID_CONTEXTUALSEARCH_CTR_RECORDER_H_
+
+#include <stddef.h>
+
+#include "base/android/jni_android.h"
+#include "components/contextual_search/browser/ctr_aggregator.h"
+#include "components/contextual_search/browser/weekly_activity_storage.h"
+
+// Provides a Java conduit to the CTRAggregator in the Contextual Search
+// component. This allows Java to access the aggregated CTR values.
+// This class also provides device-specific integer storage through its
+// associated Java class as required to implement the WeeklyActivityStorage.
+class CTRRecorder : public contextual_search::WeeklyActivityStorage {
+ public:
+  // Constructs a new CTRRecorder linked to the given Java object.
+  CTRRecorder(JNIEnv* env, jobject obj);
+  ~CTRRecorder() override;
+
+  // Calls the destructor.  Should be called when this native object is no
+  // longer needed.
+  void Destroy(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
+
+  // Records an impression.  Also records a click if |did_click| is true.
+  void RecordImpression(JNIEnv* env,

[Theresa, 2016/09/27 20:53:56]

For the methods that just call through to
components/contextual_search/browser/ctr_aggregator.h, I think it's fine to
group them together and reference that class in one comment rather than
duplicating the comments in the other ctr_aggregator.h.

[Donn Denman, 2016/09/28 00:38:43]

Done.

+                        const base::android::JavaParamRef<jobject>& obj,
+                        jboolean did_click);
+  // Returns the current week number.
+  jint GetCurrentWeekNumber(JNIEnv* env,
+                            const base::android::JavaParamRef<jobject>& obj);
+  // Returns whether there is data recorded for the previous week.
+  jboolean HasPreviousWeekData(JNIEnv* env,
+                               const base::android::JavaParamRef<jobject>& obj);
+  // Returns the number of impressions for this user for the previous week.
+  // If the data for this user is not complete for the previous week, as
+  // indicated by |HasPreviousWeekData| then NAN is returned.
+  jint GetPreviousWeekImpressions(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj);
+  // Returns the CTR for this user for the previous week.
+  // If the data for this user is not complete for the previous week, as
+  // indicated by |HasPreviousWeekData| then the result is undefined.
+  jfloat GetPreviousWeekCTR(JNIEnv* env,
+                            const base::android::JavaParamRef<jobject>& obj);
+  // Returns whether there is data recorded for the previous 28-day period that
+  // ended in the previous week.
+  jboolean HasPrevious28DayData(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj);
+  // Returns the number of impressions for this user for the 28-day period that
+  // ended in the previous week. If the data for this user is not complete for
+  // the 28-day period that ended in the previous week, as indicated by
+  // |HasPrevious28DayData| then the result is undefined.
+  jint GetPrevious28DayImpressions(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj);
+  // Returns the CTR for this user for the 28-day period that ended in the
+  // previous week. If the data for this user is not complete for the 28-day
+  // period that ended in the previous week, as indicated by
+  // |HasPrevious28DayData| then NAN is returned.
+  jfloat GetPrevious28DayCTR(JNIEnv* env,
+                             const base::android::JavaParamRef<jobject>& obj);
+
+  // WeeklyActivityStorage Overrides.
+  int ReadStorage(std::string storage_bucket) override;
+  void WriteStorage(std::string storage_bucket, int value) override;
+
+ private:
+  // The CTRAggregator that we forward requests to.
+  std::unique_ptr<contextual_search::CTRAggregator> aggregator_;
+
+  // The linked Java object.
+  base::android::ScopedJavaGlobalRef<jobject> java_object_;
+
+  DISALLOW_COPY_AND_ASSIGN(CTRRecorder);
+};
+
+bool RegisterCTRRecorder(JNIEnv* env);
+
+#endif  // CHROME_BROWSER_ANDROID_CONTEXTUALSEARCH_CTR_RECORDER_H_