Hack functionality into fake Google Play stubs

This makes the relevant tests pass

app/src/main/java/com/google/android/gms/ads/identifier/AdvertisingIdClient.java

@@ -1,18 +1,36 @@
 package com.google.android.gms.ads.identifier;
 
 import android.content.Context;
+import com.google.android.gms.common.GooglePlayServicesNotAvailableException;
+import com.google.android.gms.common.GooglePlayServicesRepairableException;
+
 
 public class AdvertisingIdClient {
 
     public static final class Info {
 
+        private String mId;
+
+        public Info() {
+            mId = "";
+        }
+
+        public Info(String id, Boolean ignored) {
+            // We need to preserve the passed ID to pass Mozilla's tests.
+            mId = id;
+        }
+
         public String getId() {
-            return "";
+            return mId;
+        }
+        
+        public String toString() {
+            return mId;
         }
 
     }
 
-    public static Info getAdvertisingIdInfo(Context context) {
+    public static Info getAdvertisingIdInfo(Context context) throws GooglePlayServicesNotAvailableException, GooglePlayServicesRepairableException {
         return new Info();
     }
 

app/src/main/java/com/google/android/gms/common/GooglePlayServicesNotAvailableException.java

@@ -1,4 +1,8 @@
 package com.google.android.gms.common;
 
 public class GooglePlayServicesNotAvailableException extends Exception {
+
+    public GooglePlayServicesNotAvailableException(int arg1) {
+    }
+
 }

app/src/main/java/com/google/android/gms/common/GooglePlayServicesRepairableException.java

@@ -1,4 +1,6 @@
 package com.google.android.gms.common;
 
 public class GooglePlayServicesRepairableException extends Exception {
+    public GooglePlayServicesRepairableException(int arg1, String arg2, Object arg3) {
+    }
 }