add GDrive provider support (#118)

* GDrive provider support
* More reliable basedir ownership
* Fix mimetype

vendor/cloud.google.com/go/trace/apiv1/doc.go

@@ -0,0 +1,54 @@
+// Copyright 2018 Google LLC
+//
+// 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
+//
+//     https://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.
+
+// AUTO-GENERATED CODE. DO NOT EDIT.
+
+// Package trace is an auto-generated package for the
+// Stackdriver Trace API.
+//
+//   NOTE: This package is in alpha. It is not stable, and is likely to change.
+//
+// Sends application trace data to Stackdriver Trace for viewing. Trace data
+// is
+// collected for all App Engine applications by default. Trace data from
+// other
+// applications can be provided using this API.
+//
+// Use the client at cloud.google.com/go/trace in preference to this.
+package trace // import "cloud.google.com/go/trace/apiv1"
+
+import (
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/metadata"
+)
+
+func insertMetadata(ctx context.Context, mds ...metadata.MD) context.Context {
+	out, _ := metadata.FromOutgoingContext(ctx)
+	out = out.Copy()
+	for _, md := range mds {
+		for k, v := range md {
+			out[k] = append(out[k], v...)
+		}
+	}
+	return metadata.NewOutgoingContext(ctx, out)
+}
+
+// DefaultAuthScopes reports the default set of authentication scopes to use with this package.
+func DefaultAuthScopes() []string {
+	return []string{
+		"https://www.googleapis.com/auth/cloud-platform",
+		"https://www.googleapis.com/auth/trace.append",
+		"https://www.googleapis.com/auth/trace.readonly",
+	}
+}