Add media router common classes and unittests.

chrome/browser/media/router/media_source.cc

+// Copyright 2015 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 "chrome/browser/media/router/media_source.h"
+
+#include "base/strings/string_util.h"
+#include "base/strings/stringprintf.h"
+#include "url/gurl.h"
+
+namespace media_router {
+
+namespace {
+
+// See: https://www.ietf.org/rfc/rfc3406.txt
+const char* kTabMediaUrnPrefix = "urn:x-org.chromium.media:source:tab";
+const char* kDesktopMediaUrnPrefix = "urn:x-org.chromium.media:source:desktop";
+const char* kDialUrnPrefix = "urn:dial-multiscreen-org:dial:application:";

[mark a. foltz, 2015/03/05 16:58:41]

This can be removed.

[Kevin M, 2015/03/05 18:34:18]

Done.

+const char* kCastUrnPrefix = "urn:x-com.google.cast:application:";
+
+}  // namespace
+
+MediaSource ForTabMediaSource(int tab_id) {
+  return base::StringPrintf("%s:%d", kTabMediaUrnPrefix, tab_id);
+}
+
+MediaSource ForDesktopMediaSource() {
+  return std::string(kDesktopMediaUrnPrefix);
+}
+
+// TODO(mfoltz): Remove when the TODO in
+// MediaSourceManager::GetDefaultMediaSource is resolved.
+MediaSource ForCastAppMediaSource(const std::string& app_id) {
+  return kCastUrnPrefix + app_id;
+}
+
+MediaSource ForPresentationUrl(const std::string& presentation_url) {
+  return presentation_url;
+}
+
+bool IsMirroringMediaSource(const MediaSource& source) {
+  return StartsWithASCII(source, kDesktopMediaUrnPrefix, true) ||
+    StartsWithASCII(source, kTabMediaUrnPrefix, true);
+}
+
+bool IsValidMediaSource(const MediaSource& source) {
+  if (IsMirroringMediaSource(source) ||
+      StartsWithASCII(source, kDialUrnPrefix, true) ||

[mark a. foltz, 2015/03/05 16:58:41]

As can this line.

[Kevin M, 2015/03/05 18:34:18]

Done.

+      StartsWithASCII(source, kCastUrnPrefix, true)) {
+    return true;
+  }
+  GURL url(source);
+  return url.is_valid() && url.SchemeIsHTTPOrHTTPS();
+}
+
+}  // namespace media_router