Add UMA metrics to track the source of homescreen icons on launch.

chrome/android/java/src/org/chromium/chrome/browser/metrics/LaunchMetrics.java

 // 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.
 
 package org.chromium.chrome.browser.metrics;
 
 import org.chromium.base.JNINamespace;
 import org.chromium.content_public.browser.WebContents;
 
 import java.util.ArrayList;
 import java.util.List;
 
 /**
  * Used for recording metrics about Chrome launches.
  */
 @JNINamespace("metrics")
 public class LaunchMetrics {
-    private static final List<String> sActivityUrls = new ArrayList<String>();
-    private static final List<String> sTabUrls = new ArrayList<String>();
+    private static class UrlSourcePair {
+        // The source member stores the origin of the url, e.g. from the add to homescreen menu
+        // item, an app banner, or unknown. The mapping of int source values to their string names
+        // is found in the C++ ShortcutInfo struct.
+        private String mUrl;
+        private int mSource;
+
+        public UrlSourcePair(String url, int source) {
+            mUrl = url;
+            mSource = source;
+        }
+
+        public String getUrl() {
+            return mUrl;
+        }
+
+        public int getSource() {
+            return mSource;
+        }
+    }
+
+    private static final List<UrlSourcePair> sActivityUrls = new ArrayList<UrlSourcePair>();
+    private static final List<UrlSourcePair> sTabUrls = new ArrayList<UrlSourcePair>();
 
     /**
-     * Records the launch of a standalone Activity for a URL (i.e. a WebappActivity).
+     * Records the launch of a standalone Activity for a URL (i.e. a WebappActivity)
+     * added from a specific source.
      * @param url URL that kicked off the Activity's creation.
+     * @param source integer id of the source from where the URL was added.
      */
-    public static void recordHomeScreenLaunchIntoStandaloneActivity(String url) {
-        sActivityUrls.add(url);
+    public static void recordHomeScreenLaunchIntoStandaloneActivity(String url, int source) {
+        sActivityUrls.add(new UrlSourcePair(url, source));
     }
 
     /**
      * Records the launch of a Tab for a URL (i.e. a Home screen shortcut).
      * @param url URL that kicked off the Tab's creation.
+     * @param source integer id of the source from where the URL was added.
      */
-    public static void recordHomeScreenLaunchIntoTab(String url) {
-        sTabUrls.add(url);
+    public static void recordHomeScreenLaunchIntoTab(String url, int source) {
+        sTabUrls.add(new UrlSourcePair(url, source));
     }
 
     /**
      * Calls out to native code to record URLs that have been launched via the Home screen.
      * This intermediate step is necessary because Activity.onCreate() may be called when
      * the native library has not yet been loaded.
      * @param webContents WebContents for the current Tab.
      */
     public static void commitLaunchMetrics(WebContents webContents) {
-        for (String url : sActivityUrls) {
-            nativeRecordLaunch(true, url, webContents);
+        for (UrlSourcePair item : sActivityUrls) {
+            nativeRecordLaunch(true, item.getUrl(), item.getSource(), webContents);
         }
-        for (String url : sTabUrls) {
-            nativeRecordLaunch(false, url, webContents);
+        for (UrlSourcePair item : sTabUrls) {
+            nativeRecordLaunch(false, item.getUrl(), item.getSource(), webContents);
         }
         sActivityUrls.clear();
         sTabUrls.clear();
     }
 
     private static native void nativeRecordLaunch(
-            boolean standalone, String url, WebContents webContents);
+            boolean standalone, String url, int source, WebContents webContents);
 }