Add a rappor metric for getting package names for custom tabs clients

chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabsConnection.java

Index: chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabsConnection.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabsConnection.java b/chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabsConnection.java
index 283b4c548036f6e415a335e14009f38df5b863ee..06cf6d96f93474ae7bd54e6722144d7d25a0a8f5 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabsConnection.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabsConnection.java
@@ -323,10 +323,16 @@ public class CustomTabsConnection extends ICustomTabsService.Stub {
         return null;
     }
 
+    /** See {@link ClientManager#getReferrerForSession(IBinder)} */
     public Referrer getReferrerForSession(IBinder session) {
         return mClientManager.getReferrerForSession(session);
     }
 
+    /** See {@link ClientManager#getClientPackageNameForSession(IBinder)} */
+    public String getClientPackageNameForSession(IBinder session) {
+        return mClientManager.getClientPackageNameForSession(session);
+    }
+
     /**
      * Notifies the application of a navigation event.
      *