LogDog: Update client/bootstrap to generate URLs.

logdog/common/viewer/url.go

Index: logdog/common/viewer/url.go
diff --git a/logdog/common/viewer/url.go b/logdog/common/viewer/url.go
new file mode 100644
index 0000000000000000000000000000000000000000..a88f385486585fc95d867bc35b3e4ce965ea367b
--- /dev/null
+++ b/logdog/common/viewer/url.go
@@ -0,0 +1,31 @@
+// Copyright 2016 The LUCI Authors. All rights reserved.
+// Use of this source code is governed under the Apache License, Version 2.0
+// that can be found in the LICENSE file.
+
+// Package viewer is a support library to interact with the LogDog web app and
+// log stream viewer.
+package viewer
+
+import (
+	"fmt"
+	"net/url"
+
+	"github.com/luci/luci-go/common/config"
+	"github.com/luci/luci-go/logdog/common/types"
+)
+
+// GetURL generates a LogDog app viewer URL for the specified streams.
+func GetURL(host string, project config.ProjectName, paths ...types.StreamPath) string {
+	query := make(url.Values, len(paths))

[Vadim Sh., 2016/10/28 03:56:53]

nit: len(paths) here is harmful.

url.Values is map[string][]string, it allocated capacity for the wrong thing

[dnj, 2016/10/28 04:00:10]

Hah you're right, didn't occur to me that every key was "s". Good catch.

+	for _, p := range paths {
+		query.Add("s", fmt.Sprintf("%s/%s", project, p))
+	}
+
+	u := url.URL{
+		Scheme:   "https",
+		Host:     host,
+		Path:     "v/",
+		RawQuery: query.Encode(),
+	}
+	return u.String()
+}