[Presentation API] Add support for multiple URLs in PresentationRequest on Media Router UI side

chrome/browser/ui/webui/media_router/cast_modes_with_media_sources.cc

+// 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 "chrome/browser/ui/webui/media_router/cast_modes_with_media_sources.h"
+
+namespace media_router {
+
+CastModesWithMediaSources::CastModesWithMediaSources() {}
+CastModesWithMediaSources::CastModesWithMediaSources(

[mark a. foltz, 2016/08/31 05:18:54]

Is the copy ctor necessary?

[takumif, 2016/09/01 21:09:25]

We need it for using the [] operator on |all_sinks_| in QueryResultManager, in
which CMWMS is used as the values in the map.

+    const CastModesWithMediaSources& other) = default;
+CastModesWithMediaSources::~CastModesWithMediaSources() {}
+
+void CastModesWithMediaSources::AddSource(
+    const MediaSource& source, MediaCastMode cast_mode) {
+  cast_modes_[cast_mode].insert(source);
+}
+
+void CastModesWithMediaSources::RemoveSource(
+    const MediaSource& source, MediaCastMode cast_mode) {
+  cast_modes_[cast_mode].erase(source);
+  if (cast_modes_[cast_mode].empty())
+    RemoveCastMode(cast_mode);
+}
+
+bool CastModesWithMediaSources::HasSource(
+    const MediaSource& source, MediaCastMode cast_mode) const {
+  if (cast_modes_.find(cast_mode) == cast_modes_.end())

[mark a. foltz, 2016/08/31 05:18:54]

Assign cast_modes_.find(cast_mode) to a local variable to avoid repeated
lookups.

[takumif, 2016/09/01 21:09:25]

Done.

+    return false;
+  return cast_modes_.at(cast_mode).find(source) !=
+      cast_modes_.at(cast_mode).end();
+}
+
+void CastModesWithMediaSources::RemoveCastMode(MediaCastMode cast_mode) {

[mark a. foltz, 2016/08/31 05:18:54]

It seems like this should only be done if the set of sources is also empty. 
Does this need to be part of the API?

[takumif, 2016/09/01 21:09:25]

No, this is no longer necessary. Removing.

+  cast_modes_.erase(cast_mode);
+}
+
+CastModeSet CastModesWithMediaSources::GetCastModes() const {
+  CastModeSet cast_mode_set;
+  for (const auto& cast_mode_pair : cast_modes_)
+    cast_mode_set.insert(cast_mode_pair.first);
+  return cast_mode_set;
+}
+
+bool CastModesWithMediaSources::IsEmpty() const {
+  return cast_modes_.empty();
+}
+
+}  // namespace media_router