[Chrome Home Survey] Adds client-side filtering

-Reorders order for doesUserQualify
-Adds filtering methods
-Adds tests for filtering methods
-Adds logging for when the last time the random # gen. was rolled
-Adds Chrome Home Force Survey check to doesUserQualify to allow for
  testing of other survey qualifications

Filtering method:
-Gets the max number from the finch config
-Rolls a random number up from 0 (inclusive) to that number (exclusive)
-If the random number = 0, process continues for user
-Else stop


Bug: 778384
Change-Id: Ie7063724614c98121e0e93c1a4b091557635015a
Reviewed-on: https://chromium-review.googlesource.com/741867
Commit-Queue: Daniel Park <danielpark@chromium.org>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#519836}

chrome/android/java/src/org/chromium/chrome/browser/survey/ChromeHomeSurveyController.java

@@ -6,12 +6,13 @@ package org.chromium.chrome.browser.survey;
 
 import android.content.Context;
 import android.content.SharedPreferences;
+import android.os.AsyncTask;
 import android.support.annotation.VisibleForTesting;
 import android.text.TextUtils;
 
 import org.chromium.base.CommandLine;
 import org.chromium.base.ContextUtils;
-import org.chromium.base.StrictModeContext;
+import org.chromium.base.ThreadUtils;
 import org.chromium.base.metrics.RecordUserAction;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.ChromeSwitches;
@@ -31,6 +32,9 @@ import org.chromium.content_public.browser.WebContents;
 import org.chromium.content_public.browser.WebContentsObserver;
 import org.chromium.ui.base.DeviceFormFactor;
 
+import java.util.Calendar;
+import java.util.Random;
+
 /**
  * Class that controls if and when to show surveys related to the Chrome Home experiment.
  */
@@ -40,13 +44,16 @@ public class ChromeHomeSurveyController {
     public static final String PARAM_NAME = "survey_override_site_id";
 
     private static final String TRIAL_NAME = "ChromeHome";
+    private static final String MAX_NUMBER = "MaxNumber";
 
     static final long ONE_WEEK_IN_MILLIS = 604800000L;
     static final String SURVEY_INFOBAR_DISMISSED_KEY = "chrome_home_survey_info_bar_dismissed";
+    static final String DATE_LAST_ROLLED_KEY = "chrome_home_date_last_rolled_for_survey";
 
     private TabModelSelector mTabModelSelector;
 
-    private ChromeHomeSurveyController() {
+    @VisibleForTesting
+    ChromeHomeSurveyController() {
         // Empty constructor.
     }
 
@@ -57,12 +64,11 @@ public class ChromeHomeSurveyController {
      *                         shown.
      */
     public static void initialize(Context context, TabModelSelector tabModelSelector) {
-        new ChromeHomeSurveyController().startDownload(context, tabModelSelector);
+        new StartDownloadIfEligibleTask(new ChromeHomeSurveyController(), context, tabModelSelector)
+                .executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
     }
 
     private void startDownload(Context context, TabModelSelector tabModelSelector) {
-        if (!doesUserQualifyForSurvey()) return;
-
         mTabModelSelector = tabModelSelector;
 
         SurveyController surveyController = SurveyController.getInstance();
@@ -86,15 +92,14 @@ public class ChromeHomeSurveyController {
     }
 
     private boolean doesUserQualifyForSurvey() {
-        if (CommandLine.getInstance().hasSwitch(ChromeSwitches.CHROME_HOME_FORCE_ENABLE_SURVEY)) {
-            return true;
-        }
         if (DeviceFormFactor.isTablet()) return false;
         if (!isUMAEnabled()) return false;
         if (AccessibilityUtil.isAccessibilityEnabled()) return false;
         if (hasInfoBarBeenDisplayed()) return false;
         if (!FeatureUtilities.isChromeHomeEnabled()) return true;
-        return wasChromeHomeEnabledForMinimumOneWeek();
+        return wasChromeHomeEnabledForMinimumOneWeek()
+                || CommandLine.getInstance().hasSwitch(
+                           ChromeSwitches.CHROME_HOME_FORCE_ENABLE_SURVEY);
     }
 
     private void onSurveyAvailable(String siteId) {
@@ -133,35 +138,30 @@ public class ChromeHomeSurveyController {
     }
 
     private boolean isUMAEnabled() {
-        try (StrictModeContext unused = StrictModeContext.allowDiskReads()) {
-            return PrivacyPreferencesManager.getInstance()
-                    .isUsageAndCrashReportingPermittedByUser();
-        }
+        return PrivacyPreferencesManager.getInstance().isUsageAndCrashReportingPermittedByUser();
     }
 
     private void showSurveyInfoBar(WebContents webContents, String siteId) {
         SurveyInfoBar.showSurveyInfoBar(
                 webContents, siteId, true, R.drawable.chrome_sync_logo, getSurveyInfoBarDelegate());
         SharedPreferences sharedPreferences = ContextUtils.getAppSharedPreferences();
-        sharedPreferences.edit().putBoolean(SURVEY_INFO_BAR_DISPLAYED_KEY, true).apply();
+        sharedPreferences.edit()
+                .putLong(SURVEY_INFO_BAR_DISPLAYED_KEY, System.currentTimeMillis())
+                .apply();
     }
 
     @VisibleForTesting
     boolean hasInfoBarBeenDisplayed() {
-        try (StrictModeContext unused = StrictModeContext.allowDiskReads()) {
         SharedPreferences sharedPreferences = ContextUtils.getAppSharedPreferences();
-            return sharedPreferences.getBoolean(SURVEY_INFO_BAR_DISPLAYED_KEY, false);
-        }
+        return sharedPreferences.getLong(SURVEY_INFO_BAR_DISPLAYED_KEY, -1L) != -1L;
     }
 
     @VisibleForTesting
     boolean wasChromeHomeEnabledForMinimumOneWeek() {
-        try (StrictModeContext unused = StrictModeContext.allowDiskReads()) {
         SharedPreferences sharedPreferences = ContextUtils.getAppSharedPreferences();
         long earliestLoggedDate = sharedPreferences.getLong(
                 ChromePreferenceManager.CHROME_HOME_SHARED_PREFERENCES_KEY, Long.MAX_VALUE);
         if (System.currentTimeMillis() - earliestLoggedDate >= ONE_WEEK_IN_MILLIS) return true;
-        }
         return false;
     }
 
@@ -175,6 +175,52 @@ public class ChromeHomeSurveyController {
         return new ChromeHomeSurveyController();
     }
 
+    /**
+     * Rolls a random number to see if the user was eligible for the survey
+     * @return Whether the user is eligible (i.e. the random number rolled was 0).
+     */
+    @VisibleForTesting
+    boolean isRandomlySelectedForSurvey() {
+        SharedPreferences preferences = ContextUtils.getAppSharedPreferences();
+        int lastDate = preferences.getInt(DATE_LAST_ROLLED_KEY, -1);
+        int today = getDayOfYear();
+        if (lastDate == today) return false;
+
+        int maxNumber = getMaxNumber();
+        if (maxNumber == -1) return false;
+
+        preferences.edit().putInt(DATE_LAST_ROLLED_KEY, today).apply();
+        return getRandomNumberUpTo(maxNumber) == 0;
+    }
+
+    /**
+     * @param max The max threshold for the random number generator.
+     * @return A random number from 0 (inclusive) to the max number (exclusive).
+     */
+    @VisibleForTesting
+    int getRandomNumberUpTo(int max) {
+        return new Random().nextInt(max);
+    }
+
+    /** @return The max number as stated in the finch config. */
+    @VisibleForTesting
+    int getMaxNumber() {
+        try {
+            String number = VariationsAssociatedData.getVariationParamValue(TRIAL_NAME, MAX_NUMBER);
+            if (TextUtils.isEmpty(number)) return -1;
+            return Integer.parseInt(number);
+        } catch (NumberFormatException e) {
+            return -1;
+        }
+    }
+
+    /** @return The day of the year for today. */
+    @VisibleForTesting
+    int getDayOfYear() {
+        ThreadUtils.assertOnBackgroundThread();
+        return Calendar.getInstance().get(Calendar.DAY_OF_YEAR);
+    }
+
     /**
      * @return The survey info bar delegate containing actions specific to the Chrome Home survey.
      */
@@ -199,4 +245,30 @@ public class ChromeHomeSurveyController {
             }
         };
     }
+
+    static class StartDownloadIfEligibleTask extends AsyncTask<Void, Void, Boolean> {
+        final ChromeHomeSurveyController mController;
+        final Context mContext;
+        final TabModelSelector mSelector;
+
+        public StartDownloadIfEligibleTask(ChromeHomeSurveyController controller, Context context,
+                TabModelSelector tabModelSelector) {
+            mController = controller;
+            mContext = context;
+            mSelector = tabModelSelector;
+        }
+
+        @Override
+        protected Boolean doInBackground(Void... params) {
+            if (!mController.doesUserQualifyForSurvey()) return false;
+            return mController.isRandomlySelectedForSurvey()
+                    || CommandLine.getInstance().hasSwitch(
+                               ChromeSwitches.CHROME_HOME_FORCE_ENABLE_SURVEY);
+        }
+
+        @Override
+        protected void onPostExecute(Boolean result) {
+            if (result) mController.startDownload(mContext, mSelector);
+        }
+    }
 }

chrome/android/junit/src/org/chromium/chrome/browser/survey/ChromeHomeSurveyControllerTest.java

@@ -59,11 +59,12 @@ public class ChromeHomeSurveyControllerTest {
 
     @Test
     public void testInfoBarDisplayedBefore() {
-        Assert.assertFalse(mController.hasInfoBarBeenDisplayed());
         Assert.assertFalse(mSharedPreferences.contains(
                 ChromeHomeSurveyController.SURVEY_INFO_BAR_DISPLAYED_KEY));
+        Assert.assertFalse(mController.hasInfoBarBeenDisplayed());
         mSharedPreferences.edit()
-                .putBoolean(ChromeHomeSurveyController.SURVEY_INFO_BAR_DISPLAYED_KEY, true)
+                .putLong(ChromeHomeSurveyController.SURVEY_INFO_BAR_DISPLAYED_KEY,
+                        System.currentTimeMillis())
                 .apply();
         Assert.assertTrue(mController.hasInfoBarBeenDisplayed());
     }
@@ -123,4 +124,68 @@ public class ChromeHomeSurveyControllerTest {
         verify(mTab, times(1)).getWebContents();
         verify(mTab, never()).isIncognito();
     }
+
+    @Test
+    public void testEligibilityRolledYesterday() {
+        mController = new RiggedSurveyController(0, 5, 10);
+        mSharedPreferences.edit().putInt(ChromeHomeSurveyController.DATE_LAST_ROLLED_KEY, 4);
+        Assert.assertTrue(mController.isRandomlySelectedForSurvey());
+    }
+
+    @Test
+    public void testEligibilityRollingTwiceSameDay() {
+        mController = new RiggedSurveyController(0, 5, 10);
+        mSharedPreferences.edit()
+                .putInt(ChromeHomeSurveyController.DATE_LAST_ROLLED_KEY, 5)
+                .apply();
+        Assert.assertFalse(mController.isRandomlySelectedForSurvey());
+    }
+
+    @Test
+    public void testEligibilityFirstTimeRollingQualifies() {
+        mController = new RiggedSurveyController(0, 5, 10);
+        Assert.assertFalse(
+                mSharedPreferences.contains(ChromeHomeSurveyController.DATE_LAST_ROLLED_KEY));
+        Assert.assertTrue(mController.isRandomlySelectedForSurvey());
+        Assert.assertEquals(
+                5, mSharedPreferences.getInt(ChromeHomeSurveyController.DATE_LAST_ROLLED_KEY, -1));
+    }
+
+    @Test
+    public void testEligibilityFirstTimeRollingDoesNotQualify() {
+        mController = new RiggedSurveyController(5, 1, 10);
+        Assert.assertFalse(
+                mSharedPreferences.contains(ChromeHomeSurveyController.DATE_LAST_ROLLED_KEY));
+        Assert.assertFalse(mController.isRandomlySelectedForSurvey());
+        Assert.assertEquals(
+                1, mSharedPreferences.getInt(ChromeHomeSurveyController.DATE_LAST_ROLLED_KEY, -1));
+    }
+
+    class RiggedSurveyController extends ChromeHomeSurveyController {
+        int mRandomNumberToReturn;
+        int mDayOfYear;
+        int mMaxNumber;
+
+        RiggedSurveyController(int randomNumberToReturn, int dayOfYear, int maxNumber) {
+            super();
+            mRandomNumberToReturn = randomNumberToReturn;
+            mDayOfYear = dayOfYear;
+            mMaxNumber = maxNumber;
+        }
+
+        @Override
+        int getRandomNumberUpTo(int max) {
+            return mRandomNumberToReturn;
+        }
+
+        @Override
+        int getDayOfYear() {
+            return mDayOfYear;
+        }
+
+        @Override
+        int getMaxNumber() {
+            return mMaxNumber;
+        }
+    }
 }