Change ImmersiveContextMus to use DesktopCaptureClient.

ui/views/widget/desktop_aura/desktop_capture_client.cc

Index: ui/views/widget/desktop_aura/desktop_capture_client.cc
diff --git a/ui/views/widget/desktop_aura/desktop_capture_client.cc b/ui/views/widget/desktop_aura/desktop_capture_client.cc
index 5ce64e9d025154dfaedc259308675d4446709e43..a86141b650a821fb32e8befd803fc28777702f34 100644
--- a/ui/views/widget/desktop_aura/desktop_capture_client.cc
+++ b/ui/views/widget/desktop_aura/desktop_capture_client.cc
@@ -15,6 +15,15 @@ namespace views {
 DesktopCaptureClient::CaptureClients*
 DesktopCaptureClient::capture_clients_ = NULL;
 
+// static
+aura::Window* DesktopCaptureClient::GetCaptureWindowGlobal() {
+  for (auto i = capture_clients_->begin(); i != capture_clients_->end(); ++i) {

[sadrul, 2017/01/25 16:40:22]

I was hoping something like this would work:

  for (auto* client : *capture_clients_) {
    if (client->capture_window_)
      return client->capture_window_;
  }

+    if ((*i)->capture_window_)
+      return (*i)->capture_window_;
+  }
+  return NULL;

[sadrul, 2017/01/25 16:40:22]

nullptr

+}
+
 DesktopCaptureClient::DesktopCaptureClient(aura::Window* root)
     : root_(root),
       capture_window_(NULL) {
@@ -90,12 +99,7 @@ aura::Window* DesktopCaptureClient::GetCaptureWindow() {
 }
 
 aura::Window* DesktopCaptureClient::GetGlobalCaptureWindow() {
-  for (CaptureClients::iterator i = capture_clients_->begin();
-       i != capture_clients_->end(); ++i) {
-    if ((*i)->capture_window_)
-      return (*i)->capture_window_;
-  }
-  return NULL;
+  return GetCaptureWindowGlobal();
 }
 
 void DesktopCaptureClient::AddObserver(