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

chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/CTRRecorder.java

Index: chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/CTRRecorder.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/CTRRecorder.java b/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/CTRRecorder.java
new file mode 100644
index 0000000000000000000000000000000000000000..aff1559ab37332b1c8aa3f912d70e04bd2b0b126
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/CTRRecorder.java
@@ -0,0 +1,123 @@
+// 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.
+
+package org.chromium.chrome.browser.contextualsearch;
+
+import android.content.Context;
+
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.chrome.browser.preferences.ChromePreferenceManager;
+
+/**
+ * Heuristic for CTR Recording and logging.
+ * Records impressions when the Bar is dismissed.
+ * Logs CTR per user in UMA for the previous week and 28-day period.
+ * This class also implements the device-based native integer storage required by the
+ * native {@code CTRAggregator} class.
+ */
+public class CTRRecorder extends ContextualSearchHeuristic {
+    private long mNativePointer;
+
+    private static Integer sPreviousWeekCTRCache;
+    private static Integer sPrevious28DayCTRCache;
+
+    private final ChromePreferenceManager mPreferenceManager;
+
+    /**
+     * Constructs an object that tracks impressions and clicks per user to produce CTR and
+     * impression
+     * metrics.
+     * @param context An Android Context.
+     */
+    CTRRecorder(Context context) {
+        mPreferenceManager = ChromePreferenceManager.getInstance(context);
+
+        // This needs to be done last in this constructor because the native code may call
+        // into this object.
+        mNativePointer = nativeInit();
+    }
+
+    /**
+     * This method should be called to clean up storage when an instance of this class is
+     * no longer in use.
+     */
+    public void destroy() {
+        if (mNativePointer != 0L) {
+            nativeDestroy(mNativePointer);
+        }
+    }
+
+    // ============================================================================================
+    // ContextualSearchHeurisitc overrides.
+    // ============================================================================================
+
+    @Override
+    protected boolean isConditionSatisfied() {
+        return false;
+    }
+
+    @Override
+    protected void logConditionState() {

[marq (ping after 24h), 2016/08/30 08:38:13]

Is there some reason this logic is in the Android layer and not part of the
shared component?

[Donn Denman, 2016/08/30 16:49:24]

Good question.  Our current native code doesn't know anything about whether the
panel was seen or not, and that's the critical part of what we're logging here. 
 Having said that, we are planning to move the Tap suppression logic to native
this cycle, and we plan to move the "log-results-seen" logic too.  We should
take note that the "log-signals" should also be moved, so code like this doesn't
linger in the Android-only section when it could be shared.

Make sense? 

+        // Since the CTR for previous time periods rarely changes, we cache them here to avoid
+        // multiple writes to the UMA log.  Multiple writes will still happen across multiple
+        // sessions but they will be greatly reduced.
+        if (nativeHasPreviousWeekData(mNativePointer)) {
+            int previousWeekCTR = (int) (100 * nativeGetPreviousWeekCTR(mNativePointer));
+            if (sPreviousWeekCTRCache == null || sPreviousWeekCTRCache != previousWeekCTR) {
+                sPreviousWeekCTRCache = previousWeekCTR;
+                ContextualSearchUma.logPreviousWeekCTR(previousWeekCTR);
+            }
+        }
+        if (nativeHasPrevious28DayData(mNativePointer)) {
+            int previous28DayCTR = (int) (100 * nativeGetPrevious28DayCTR(mNativePointer));
+            if (sPrevious28DayCTRCache == null || sPrevious28DayCTRCache != previous28DayCTR) {
+                sPrevious28DayCTRCache = previous28DayCTR;
+                ContextualSearchUma.logPrevious28DayCTR(previous28DayCTR);
+            }
+        }
+    }
+
+    @Override
+    protected void logResultsSeen(boolean wasSearchContentViewSeen, boolean wasActivatedByTap) {
+        if (wasActivatedByTap) {
+            nativeRecordImpression(mNativePointer, wasSearchContentViewSeen);
+        }
+    }
+
+    // ============================================================================================
+    // Device integer storage.
+    // ============================================================================================
+
+    @CalledByNative
+    void writeInt(String key, int value) {
+        mPreferenceManager.writeInt(key, value);
+    }
+
+    @CalledByNative
+    int readInt(String key) {
+        return mPreferenceManager.readInt(key);
+    }
+
+    // ============================================================================================
+    // Native callback support.
+    // ============================================================================================
+
+    @CalledByNative
+    private void clearNativePointer() {
+        assert mNativePointer != 0;
+        mNativePointer = 0;
+    }
+
+    // ============================================================================================
+    // Native methods.
+    // ============================================================================================
+    private native long nativeInit();
+    private native void nativeDestroy(long nativeCTRRecorder);
+
+    private native void nativeRecordImpression(long nativeCTRRecorder, boolean wasSeen);
+    private native boolean nativeHasPreviousWeekData(long nativeCTRRecorder);
+    private native float nativeGetPreviousWeekCTR(long nativeCTRRecorder);
+    private native boolean nativeHasPrevious28DayData(long nativeCTRRecorder);
+    private native float nativeGetPrevious28DayCTR(long nativeCTRRecorder);
+}