perfetto-ui: Fix copyright headers

Half our copyright headers where:
// Copyright
// [...]

An the other half where:
/*
 * Copyright [...]
 */

Which was frustrating me, the // form seems to be more common inside
Google so unify on that.

Change-Id: I1352ca3df88b264d9d026b293eae840c16224b5a
diff --git a/ui/src/frontend/track.ts b/ui/src/frontend/track.ts
index af01753..4f8fcbf 100644
--- a/ui/src/frontend/track.ts
+++ b/ui/src/frontend/track.ts
@@ -1,18 +1,16 @@
-/*
- * Copyright (C) 2018 The Android Open Source Project
- *
- * 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.
- */
+// Copyright (C) 2018 The Android Open Source Project
+//
+// 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 * as m from 'mithril';
 import {TrackShell} from './track_shell';