Add a header when fetching pages under the DMServer URL.

components/policy/core/browser/policy_header_io_helper.cc

Index: components/policy/core/browser/policy_header_io_helper.cc
diff --git a/components/policy/core/browser/policy_header_io_helper.cc b/components/policy/core/browser/policy_header_io_helper.cc
new file mode 100644
index 0000000000000000000000000000000000000000..2fbdb5a59a5dfd19f547ea72c39025bf03a64b6b
--- /dev/null
+++ b/components/policy/core/browser/policy_header_io_helper.cc
@@ -0,0 +1,59 @@
+// Copyright (c) 2013 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 "components/policy/core/browser/policy_header_io_helper.h"
+
+#include "base/bind.h"
+#include "base/location.h"
+#include "base/sequenced_task_runner.h"
+#include "net/url_request/url_request.h"
+
+namespace {
+
+// The name of the header containing the policy information.
+const char kChromePolicyHeader[] = "Chrome-Policy-Posture";
+
+}  // namespace
+
+namespace policy {
+
+PolicyHeaderIOHelper::PolicyHeaderIOHelper(
+    const std::string& server_url,
+    const std::string& initial_header_value,
+    const scoped_refptr<base::SequencedTaskRunner>& task_runner)
+    : server_url_(server_url),
+      io_task_runner_(task_runner),
+      policy_header_(initial_header_value) {
+}
+
+PolicyHeaderIOHelper::~PolicyHeaderIOHelper() {
+}
+
+// Sets any necessary policy headers on the passed request.
+void PolicyHeaderIOHelper::AddPolicyHeaders(net::URLRequest* request) const {
+  DCHECK(io_task_runner_->RunsTasksOnCurrentThread());
+  const GURL& url = request->url();
+  if (!policy_header_.empty() &&
+      url.spec().compare(0, server_url_.size(), server_url_) == 0) {
+    request->SetExtraRequestHeaderByName(kChromePolicyHeader,
+                                         policy_header_,
+                                         true /* overwrite */);
+  }
+}
+
+void PolicyHeaderIOHelper::UpdateHeader(const std::string& new_header) {
+  // Post a task to the IO thread to modify this.
+  io_task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&PolicyHeaderIOHelper::UpdateHeaderOnIOThread,
+                 base::Unretained(this), new_header));
+}
+
+void PolicyHeaderIOHelper::UpdateHeaderOnIOThread(
+    const std::string& new_header) {
+  DCHECK(io_task_runner_->RunsTasksOnCurrentThread());
+  policy_header_ = new_header;
+}
+
+}  // namespace policy