Add support for a virtual display on ChromeOS

content/public/browser/desktop_media_id.cc

Index: content/public/browser/desktop_media_id.cc
diff --git a/content/public/browser/desktop_media_id.cc b/content/public/browser/desktop_media_id.cc
index 7817766e4d3e61de7ecd159d032a3cddb23b9dc8..c5351884b1229367e195b88d1487d60ff7d4244d 100644
--- a/content/public/browser/desktop_media_id.cc
+++ b/content/public/browser/desktop_media_id.cc
@@ -49,16 +49,29 @@ class AuraWindowRegistry : public aura::WindowObserver {
     return (it != id_to_window_map_.end()) ? it->second : nullptr;
   }
 
+  void RegisterVirtualScreenWindow(aura::Window* window) {
+    DCHECK(!virtual_screen_window_);
+    virtual_screen_window_ = window;
+    window->AddObserver(this);
+  }
+
+  aura::Window* GetVirtualScreenWindow() { return virtual_screen_window_; }
+
  private:
   friend struct DefaultSingletonTraits<AuraWindowRegistry>;
 
   AuraWindowRegistry()
-      : next_id_(1) {
+      : next_id_(1),
+        virtual_screen_window_(nullptr) {
   }
   ~AuraWindowRegistry() override {}
 
   // WindowObserver overrides.
   void OnWindowDestroying(aura::Window* window) override {
+    if (window == virtual_screen_window_) {
+      virtual_screen_window_ = nullptr;
+      return;
+    }
     std::map<aura::Window*, int>::iterator it = window_to_id_map_.find(window);
     DCHECK(it != window_to_id_map_.end());
     id_to_window_map_.erase(it->second);
@@ -69,6 +82,8 @@ class AuraWindowRegistry : public aura::WindowObserver {
   std::map<aura::Window*, int> window_to_id_map_;
   std::map<int, aura::Window*> id_to_window_map_;
 
+  aura::Window* virtual_screen_window_;
+
   DISALLOW_COPY_AND_ASSIGN(AuraWindowRegistry);
 };
 
@@ -81,6 +96,7 @@ namespace content {
 const char kScreenPrefix[] = "screen";
 const char kWindowPrefix[] = "window";
 const char kAuraWindowPrefix[] = "aura_window";
+const char kAuraVirtualScreenPrefix[] = "aura_virtual_screen";
 
 #if defined(USE_AURA)
 
@@ -92,7 +108,15 @@ DesktopMediaID DesktopMediaID::RegisterAuraWindow(aura::Window* window) {
 }
 
 // static
+void DesktopMediaID::RegisterVirtualScreenAuraWindow(aura::Window* window) {
+  AuraWindowRegistry::GetInstance()->RegisterVirtualScreenWindow(window);
+}
+
+// static
 aura::Window* DesktopMediaID::GetAuraWindowById(const DesktopMediaID& id) {
+  if (id.type == TYPE_AURA_VIRTUAL_SCREEN)
+    return AuraWindowRegistry::GetInstance()->GetVirtualScreenWindow();
+
   DCHECK_EQ(id.type, TYPE_AURA_WINDOW);
   return AuraWindowRegistry::GetInstance()->GetWindowById(id.id);
 }
@@ -114,6 +138,8 @@ DesktopMediaID DesktopMediaID::Parse(const std::string& str) {
     type = TYPE_WINDOW;
   } else if (parts[0] == kAuraWindowPrefix) {
     type = TYPE_AURA_WINDOW;
+  } else if (parts[0] == kAuraVirtualScreenPrefix) {
+    type = TYPE_AURA_VIRTUAL_SCREEN;
   } else {
     return DesktopMediaID(TYPE_NONE, 0);
   }
@@ -140,6 +166,9 @@ std::string DesktopMediaID::ToString() {
     case TYPE_AURA_WINDOW:
       prefix = kAuraWindowPrefix;
       break;
+    case TYPE_AURA_VIRTUAL_SCREEN:
+      prefix = kAuraVirtualScreenPrefix;
+      break;
   }
   DCHECK(!prefix.empty());