Added license headers

src/main/java/com/google/firebase/internal/ApiClientUtils.java

@@ -1,3 +1,19 @@
+/*
+ * Copyright 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package com.google.firebase.internal;
 
 import com.google.api.client.http.HttpRequestFactory;

src/main/java/com/google/firebase/messaging/FirebaseMessagingClient.java

@@ -155,7 +155,7 @@ private BatchRequest newBatchRequest(
     final GenericUrl sendUrl = new GenericUrl(fcmSendUrl);
     for (Message message : messages) {
       // Using a separate request factory without authorization is faster for large batches.
-      // A simple perf test showed a 400-500ms speed up for batches of 1000 messages.
+      // A simple performance test showed a 400-500ms speed up for batches of 1000 messages.
       HttpRequest request = childRequestFactory.buildPostRequest(
           sendUrl,
           new JsonHttpContent(jsonFactory, message.wrapForTransport(dryRun)));
@@ -182,6 +182,7 @@ private FirebaseMessagingException createExceptionFromResponse(HttpResponseExcep
         // ignored
       }
     }
+
     return newException(response, e);
   }
 
@@ -205,6 +206,7 @@ private static FirebaseMessagingException newException(
     if (code == null) {
       code = UNKNOWN_ERROR;
     }
+
     String msg = response.getErrorMessage();
     if (Strings.isNullOrEmpty(msg)) {
       if (e != null) {
@@ -214,6 +216,7 @@ private static FirebaseMessagingException newException(
         msg = String.format("Unexpected HTTP response: %s", response.toString());
       }
     }
+
     return new FirebaseMessagingException(code, msg, e);
   }
 

src/main/java/com/google/firebase/messaging/InstanceIdClient.java

@@ -1,3 +1,19 @@
+/*
+ * Copyright 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package com.google.firebase.messaging;
 
 import com.google.api.client.http.GenericUrl;