travis: check for copyright in sources

.travis.yml

@@ -28,6 +28,7 @@ before_install:
 
 script:
   - "! git grep -I ' $'" # Fail on trailing whitespace in non-binary files
+  - "! git grep -L --name-only 'Copyright [0-9]* Google' | grep -v third_party | egrep '\\.(m|h|cc|mm|c)$'"
   - ./scripts/style.sh test-only # Validate clang-format compliance
   - |
     if [ $SKIP_FIREBASE != 1 ]; then

Firestore/Source/Core/FSTListenSequence.m

@@ -1,3 +1,19 @@
+/*
+ * Copyright 2018 Google
+ *
+ * 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.
+ */
+
 #import "FSTListenSequence.h"
 
 NS_ASSUME_NONNULL_BEGIN

patch/FirebaseAnalytics.h

@@ -1,3 +1,19 @@
+/*
+ * Copyright 2018 Google
+ *
+ * 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.
+ */
+
 // Firebase Analytics umbrella header for interoperating with open source builds
 // More details at https://github.com/firebase/firebase-ios-sdk#source-pod-integration