Allows client to access auth token from command line specified file.

blimp/common/get_client_token.cc

Index: blimp/common/get_client_token.cc
diff --git a/blimp/common/get_client_token.cc b/blimp/common/get_client_token.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e34583be04cbc74514858112aa40ef23d50da1b0
--- /dev/null
+++ b/blimp/common/get_client_token.cc
@@ -0,0 +1,24 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/strings/string_util.h"
+#include "blimp/common/get_client_token.h"
+#include "blimp/engine/app/switches.h"

[Kevin M, 2016/05/10 18:06:35]

Consider promote shared switches to something under "common"; we shouldn't have
cycles in our dependency graph.

[CJ, 2016/05/10 20:58:06]

Done.

+
+namespace blimp {
+
+std::string GetClientToken(const base::CommandLine& cmd_line) {

[Kevin M, 2016/05/10 18:06:35]

Existing test code already manipulates the current process' command line, so
taking it as a parameter is an unnecessary burden on callers. Recommend making
this function no-arg and having it just get the command line object itself.

[CJ, 2016/05/10 20:58:06]

Although I agree, would this have any impact on the ease of testability? Just
wondering before I go and change it. 

+  std::string file_contents;
+  const base::FilePath path = cmd_line.GetSwitchValuePath(
+      engine::kClientTokenPath);
+  if (!base::ReadFileToString(path, &file_contents)) {
+    LOG(ERROR) << "Could not read client token file at "
+               << (path.empty() ? "(not provided)" : path.AsUTF8Unsafe());
+  }
+  return base::CollapseWhitespaceASCII(file_contents, true);
+}
+
+}  // namespace blimp