Improve the resolution of the menu item homescreen launch source metric.

chrome/browser/android/metrics/launch_metrics.cc

Index: chrome/browser/android/metrics/launch_metrics.cc
diff --git a/chrome/browser/android/metrics/launch_metrics.cc b/chrome/browser/android/metrics/launch_metrics.cc
index b231fe5697b665e5e31a6b52a16e7c73e27fe37f..3597364bca5392636d7decab49537891d2665779 100644
--- a/chrome/browser/android/metrics/launch_metrics.cc
+++ b/chrome/browser/android/metrics/launch_metrics.cc
@@ -40,11 +40,25 @@ static void RecordLaunch(JNIEnv* env,
                          const JavaParamRef<jstring>& jurl,
                          int source,
                          const JavaParamRef<jobject>& jweb_contents) {
-  GURL url(base::android::ConvertJavaStringToUTF8(env, jurl));
+  // Interpolate the legacy ADD_TO_HOMESCREEN source into standalone/shortcut.
+  // Unfortunately, we cannot concretely determine whether a standalone add to
+  // homescreen source means a full PWA (with service worker) or a site that has
+  // a manifest with display: standalone.
+  int histogram_source = source;
+  if (histogram_source == ShortcutInfo::SOURCE_ADD_TO_HOMESCREEN_DEPRECATED) {
+    if (standalone)
+      histogram_source = ShortcutInfo::SOURCE_ADD_TO_HOMESCREEN_STANDALONE;
+    else
+      histogram_source = ShortcutInfo::SOURCE_ADD_TO_HOMESCREEN_SHORTCUT;
+  }
 
+  GURL url(base::android::ConvertJavaStringToUTF8(env, jurl));
   content::WebContents* web_contents =
       content::WebContents::FromJavaWebContents(jweb_contents);
-  if (web_contents && source == ShortcutInfo::SOURCE_APP_BANNER) {
+
+  if (web_contents &&
+      (histogram_source == ShortcutInfo::SOURCE_APP_BANNER ||
+       histogram_source == ShortcutInfo::SOURCE_ADD_TO_HOMESCREEN_PWA)) {
     // What a user has installed on the Home screen can become disconnected from
     // what Chrome believes is on the Home screen if the user clears their data.
     // Use the launch as a signal that the shortcut still exists.
@@ -61,18 +75,32 @@ static void RecordLaunch(JNIEnv* env,
   }
 
   std::string rappor_metric_source;
-  if (source == ShortcutInfo::SOURCE_ADD_TO_HOMESCREEN)
-    rappor_metric_source = "Launch.HomeScreenSource.AddToHomeScreen";
-  else if (source == ShortcutInfo::SOURCE_APP_BANNER)
-    rappor_metric_source = "Launch.HomeScreenSource.AppBanner";
-  else if (source == ShortcutInfo::SOURCE_BOOKMARK_NAVIGATOR_WIDGET)
-    rappor_metric_source = "Launch.HomeScreenSource.BookmarkNavigatorWidget";
-  else if (source == ShortcutInfo::SOURCE_BOOKMARK_SHORTCUT_WIDGET)
-    rappor_metric_source = "Launch.HomeScreenSource.BookmarkShortcutWidget";
-  else
-    rappor_metric_source = "Launch.HomeScreenSource.Unknown";
-
-  UMA_HISTOGRAM_ENUMERATION("Launch.HomeScreenSource", source,
+  switch (histogram_source) {
+    case ShortcutInfo::SOURCE_ADD_TO_HOMESCREEN_DEPRECATED:
+    case ShortcutInfo::SOURCE_ADD_TO_HOMESCREEN_PWA:
+    case ShortcutInfo::SOURCE_ADD_TO_HOMESCREEN_STANDALONE:
+    case ShortcutInfo::SOURCE_ADD_TO_HOMESCREEN_SHORTCUT:
+      rappor_metric_source = "Launch.HomeScreenSource.AddToHomeScreen";
+      break;
+    case ShortcutInfo::SOURCE_APP_BANNER:
+      rappor_metric_source = "Launch.HomeScreenSource.AppBanner";
+      break;
+    case ShortcutInfo::SOURCE_BOOKMARK_NAVIGATOR_WIDGET:
+      rappor_metric_source = "Launch.HomeScreenSource.BookmarkNavigatorWidget";
+      break;
+    case ShortcutInfo::SOURCE_BOOKMARK_SHORTCUT_WIDGET:
+      rappor_metric_source = "Launch.HomeScreenSource.BookmarkShortcutWidget";
+      break;
+    case ShortcutInfo::SOURCE_NOTIFICATION:
+      rappor_metric_source = "Launch.HomeScreenSource.Notification";
+      break;
+    case ShortcutInfo::SOURCE_UNKNOWN:
+    case ShortcutInfo::SOURCE_COUNT:

[gone, 2017/02/14 19:44:51]

Should SOURCE_COUNT just fall into default:?

[dominickn, 2017/02/14 23:02:14]

I didn't want to have a default case to ensure that any new additions had to be
explicitly accounted for.

+      rappor_metric_source = "Launch.HomeScreenSource.Unknown";
+      break;
+  }
+
+  UMA_HISTOGRAM_ENUMERATION("Launch.HomeScreenSource", histogram_source,
                             ShortcutInfo::SOURCE_COUNT);
 
   rappor::SampleDomainAndRegistryFromGURL(g_browser_process->rappor_service(),