[Android] Omnibox Placeholder Experiment

chrome/android/java/src/org/chromium/chrome/browser/omnibox/OmniboxPlaceholderFieldTrial.java

Index: chrome/android/java/src/org/chromium/chrome/browser/omnibox/OmniboxPlaceholderFieldTrial.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/omnibox/OmniboxPlaceholderFieldTrial.java b/chrome/android/java/src/org/chromium/chrome/browser/omnibox/OmniboxPlaceholderFieldTrial.java
new file mode 100644
index 0000000000000000000000000000000000000000..52bc2aaf3f547f72c6c363add5d0fa9cbc2bb3d2
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/omnibox/OmniboxPlaceholderFieldTrial.java
@@ -0,0 +1,95 @@
+// Copyright 2017 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.omnibox;
+
+import android.content.res.Resources;
+
+import org.chromium.base.CommandLine;
+import org.chromium.base.ContextUtils;
+import org.chromium.base.FieldTrialList;
+import org.chromium.chrome.R;
+import org.chromium.chrome.browser.ChromeSwitches;
+import org.chromium.chrome.browser.preferences.ChromePreferenceManager;
+
+/**
+ * Provides Field Trial support for Omnibox Placeholder Experiment.
+ */
+public class OmniboxPlaceholderFieldTrial {
+    private static final String FIELD_TRIAL_NAME = "OmniboxPlaceholderExperiment";
+    private static final String GROUP_SEARCH_OR_TYPE_URL = "SearchOrTypeUrl";
+    private static final String GROUP_SEARCH_OR_TYPE_WEBSITE_NAME = "SearchOrTypeWebsiteName";
+    private static final String GROUP_SEARCH_THE_WEB = "SearchTheWeb";
+    private static final String GROUP_ENTER_A_SEARCH_OR_WEBSITE = "EnterASearchOrWebsite";
+    private static final String GROUP_SEARCH_NEWS = "SearchNews";
+    private static final String GROUP_SEARCH_RECIPES = "SearchRecipes";
+    private static final String GROUP_SEARCH_WEATHER = "SearchWeather";
+    private static final String GROUP_BLANK = "Blank";
+
+    private static String sCachedHint = null;
+
+    /** Prevent initialization of this class. */
+    private OmniboxPlaceholderFieldTrial() {}
+
+    /**
+     * Caches omnibox placeholder experiment group to shared preferences.
+     */
+    public static void cacheOmniboxPlaceholderGroup() {
+        String groupName = FieldTrialList.findFullName(FIELD_TRIAL_NAME);

[Ted C, 2017/05/30 22:14:28]

I "think" they are suggesting most experiments to use the FeatureList (see
ChromeFeatureList.java) path instead of FieldTrialList.

I guess I'll defer to the metrics reviewer, but I was under the impression they
would want you to do something like:

if (ChromeFeatureList.isEnabled(FIELD_TRIAL_NAME) {
    groupName = ChromeFeatureList.getFieldTrialParamByFeature(
            FIELD_TRIAL_NAME, STRING_OVERRIDE_TYPE);
}

The idea is that would give you more flexibility if you wanted to run multiple
experiment arms with the same param so you could ensure the groups behave
similarly.

+
+        if (CommandLine.isInitialized()) {
+            CommandLine instance = CommandLine.getInstance();
+            if (instance.hasSwitch(ChromeSwitches.OMNIBOX_PLACEHOLDER_EXPERIMENT)) {
+                groupName = instance.getSwitchValue(ChromeSwitches.OMNIBOX_PLACEHOLDER_EXPERIMENT);
+            }
+        }
+        ChromePreferenceManager.getInstance().setOmniboxPlaceholderGroup(groupName);
+    }
+
+    /**
+     * Set ominibox placeholder text to static variable sCachedHint
+     */
+    private static void setOmniboxPlaceholder() {

[Ted C, 2017/05/30 22:14:28]

nit, but I would call this initOmniboxPlaceholder (set to me implies taking a
param)

[huayinz, 2017/05/31 00:01:39]

Done.

+        // setUrlBarHint is only called once when hint is not cached to static variable sCachedHint.
+        // This is to keep consistency on showing same hint to user in one session.
+        String groupName = ChromePreferenceManager.getInstance().getOmniboxPlaceholderGroup();
+        Resources resources = ContextUtils.getApplicationContext().getResources();
+        switch (groupName) {
+            case GROUP_SEARCH_OR_TYPE_URL:
+                sCachedHint = resources.getString(R.string.search_or_type_url);
+                break;
+            case GROUP_SEARCH_OR_TYPE_WEBSITE_NAME:
+                sCachedHint = resources.getString(R.string.search_or_type_website_name);
+                break;
+            case GROUP_SEARCH_THE_WEB:
+                sCachedHint = resources.getString(R.string.search_the_web);
+                break;
+            case GROUP_ENTER_A_SEARCH_OR_WEBSITE:
+                sCachedHint = resources.getString(R.string.enter_a_search_or_website);
+                break;
+            case GROUP_SEARCH_NEWS:
+                sCachedHint = resources.getString(R.string.search_news);
+                break;
+            case GROUP_SEARCH_RECIPES:
+                sCachedHint = resources.getString(R.string.search_recipes);
+                break;
+            case GROUP_SEARCH_WEATHER:
+                sCachedHint = resources.getString(R.string.search_weather);
+                break;
+            case GROUP_BLANK:
+                sCachedHint = "";
+                break;
+            default:
+                sCachedHint = resources.getString(R.string.search_or_type_url);
+        }
+    }
+
+    /**
+     * @return String of hint text to show in omnibox url bar.
+     */
+    public static String getOmniboxPlaceholder() {
+        if (sCachedHint == null) setOmniboxPlaceholder();
+        return sCachedHint;
+    }
+}