Update to CEF 81.2.24

- Added code comments to the MediaRouter demo
- Added a Lazarus version of the MediaRouter demo

demos/Delphi_VCL/MediaRouter/uMediaRouterFrm.pas

@@ -72,7 +72,6 @@ type
     CreateRouteBtn: TButton;
     CentralPnl: TPanel;
     SourcePnl: TPanel;
-    SourceURNEdt: TEdit;
     SourceLblPnl: TPanel;
     SourceURNLbl: TLabel;
     RoutesGbx: TGroupBox;
@@ -90,6 +89,7 @@ type
     NotifyRoutesBtn: TButton;
     ClearLogPnl: TPanel;
     ClearLogBtn: TButton;
+    SourceURNCbx: TComboBox;
 
     procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);
     procedure FormCreate(Sender: TObject);
@@ -115,6 +115,7 @@ type
     procedure NotifyRoutesBtnClick(Sender: TObject);
     procedure ClearLogBtnClick(Sender: TObject);
     procedure MessageMemChange(Sender: TObject);
+    procedure RoutesLbxClick(Sender: TObject);
 
   protected
     // Variables to control when can we destroy the form safely
@@ -162,16 +163,63 @@ uses
   {$ENDIF}
   uCEFMiscFunctions;
 
+// This demo can use a MediaRouter to communicate with devices on the local
+// network via the CAST and DIAL protocols.
+
+// TChromium exposes all the ICefMediaObserver events and the ICefMediaRouter
+// methods to show the available devices, to established communication routes
+// and to send messages to those devices.
+
+// Follow these steps to test this demo :
+
+// STEP 1
+// ------
+// Turn on your ChromeCast receiver. It can be an Android TV or similar device
+// like a Xiaomi MiBox. It must be on the same local network as the computer
+// running this demo.
+
+// STEP 2
+// ------
+// Run this demo and wait a few seconds. It will show all the available devices
+// in the local network and the protocol used to communicate with them.
+// In the case of the MiBox device it shows a DIAL and a CAST "sink" but after
+// a couple of secods the list is updated and it only shows the CAST sink.
+
+// STEP 3
+// ------
+// Select the CAST sink and click on the "Create route" button. This button will
+// use the "Source URN" value to create the route and that value has a CAST URN
+// with the "Application ID" of the "Default Media Receiver", which is CC1AD845.
+// This ID can be used for tests.
+
+// STEP 4
+// ------
+// The "Established routes" box will show the routes that you created.
+
+// STEP 5
+// ------
+// Select the route, type the message and click on the "Send message" button.
+
+// STEP 6
+// ------
+// Click on the "Terminate route" button.
+
+// WARNING
+// =======
+// This demo has a known bug when you close the form and it will crash.
+
+// References :
+// ============
+// https://bitbucket.org/chromiumembedded/cef/issues/2900/add-mediarouter-support-for-cast-receiver
+// https://blog.oakbits.com/google-cast-protocol-overview.html
+// https://developers.google.com/cast/docs/developers
+// https://gist.github.com/jloutsenhizer/8855258
+
 procedure CreateGlobalCEFApp;
 begin
   GlobalCEFApp             := TCefApplication.Create;
   GlobalCEFApp.LogFile     := 'debug.log';
-  GlobalCEFApp.LogSeverity := LOGSEVERITY_INFO; //LOGSEVERITY_VERBOSE;
-  {
-  GlobalCEFApp.FrameworkDirPath     := 'c:\cef';
-  GlobalCEFApp.ResourcesDirPath     := 'c:\cef';
-  GlobalCEFApp.LocalesDirPath       := 'c:\cef\locales';
-  }
+  GlobalCEFApp.LogSeverity := LOGSEVERITY_INFO;
 end;
 
 procedure TMediaRouterFrm.Chromium1AfterCreated(Sender: TObject;
@@ -411,6 +459,8 @@ begin
     if (FLog <> nil) and (FLog.Count > 0) then
       begin
         LogMem.Lines.AddStrings(FLog);
+        LogMem.SelLength := 0;
+        LogMem.SelStart  := Length(LogMem.Text);
         FLog.Clear;
       end;
   finally
@@ -427,6 +477,11 @@ begin
   UpdateButtons;
 end;
 
+procedure TMediaRouterFrm.RoutesLbxClick(Sender: TObject);
+begin
+  UpdateButtons;
+end;
+
 procedure TMediaRouterFrm.RefreshRoutesMsg(var aMessage : TMessage);
 begin
   if FClosing then exit;
@@ -572,7 +627,7 @@ var
   TempURN, TempErrorMsg : string;
   TempSource : ICefMediaSource;
 begin
-  TempURN := trim(SourceURNEdt.Text);
+  TempURN := trim(SourceURNCbx.Text);
 
   if (length(TempURN) = 0) then
     begin
@@ -619,6 +674,7 @@ begin
         end;
     end;
   finally
+    TempSource := nil;
     FMediaCS.Release;
     if (length(TempErrorMsg) > 0) then AddLogEntry(TempErrorMsg);
   end;
@@ -682,7 +738,7 @@ begin
                         (length(trim(MessageMem.Lines.Text)) > 0);
 
   CreateRouteBtn.Enabled := not(TerminateRouteBtn.Enabled) and
-                            (length(trim(SourceURNEdt.Text)) > 0) and
+                            (length(trim(SourceURNCbx.Text)) > 0) and
                             (SinksLbx.ItemIndex >= 0) and
                             (SinksLbx.Items.Count > 0);
 end;