Always run TryCloseBrowser in the CEF UI thread

source/uCEFChromiumCore.pas

@@ -117,6 +117,7 @@ type
       FHTTPSUpgrade             : TCefState;
       FHSTSPolicyBypassList     : ustring;
       FCredentialsService       : TCefState;
+      FTryingToCloseBrowser     : boolean;
 
       {$IFDEF LINUX}
       FXDisplay                 : PXDisplay;
@@ -694,6 +695,7 @@ type
       procedure doSetAudioMuted(aValue : boolean); virtual;
       procedure doToggleAudioMuted; virtual;
       procedure doEnableFocus; virtual;
+      function  doTryCloseBrowser : boolean; virtual;
 
       function  MustCreateAudioHandler : boolean; virtual;
       function  MustCreateCommandHandler : boolean; virtual;
@@ -3979,6 +3981,7 @@ begin
   FHTTPSUpgrade            := STATE_DEFAULT;
   FHSTSPolicyBypassList    := '';
   FCredentialsService      := STATE_DEFAULT;
+  FTryingToCloseBrowser    := False;
   {$IFDEF LINUX}
   FXDisplay                := nil;
   {$ENDIF}
@@ -4867,8 +4870,13 @@ end;
 procedure TChromiumCore.CloseBrowser(aForceClose : boolean);
 begin
   if Initialized then
+    begin
+      if (RuntimeStyle <> CEF_RUNTIME_STYLE_ALLOY) then
+        SetBrowserIsClosing(browser.Identifier);
+
       Browser.Host.CloseBrowser(aForceClose);
     end;
+end;
 
 procedure TChromiumCore.CloseAllBrowsers;
 begin
@@ -4882,9 +4890,26 @@ begin
 end;
 
 function TChromiumCore.TryCloseBrowser : boolean;
+var
+  TempTask : ICefTask;
 begin
   if Initialized then
-    Result := Browser.Host.TryCloseBrowser
+    begin
+      if FTryingToCloseBrowser then
+        Result := False
+       else
+        if CefCurrentlyOn(TID_UI) then
+          Result := doTryCloseBrowser
+         else
+          try
+            Result := False;
+            FTryingToCloseBrowser := True;
+            TempTask := TCefTryCloseBrowserTask.Create(self);
+            CefPostTask(TID_UI, TempTask);
+          finally
+            TempTask := nil;
+          end;
+    end
    else
     Result := True;
 end;
@@ -5196,7 +5221,8 @@ begin
   if Initialized then
     begin
       TempFrame := Browser.MainFrame;
-      if (TempFrame <> nil) and TempFrame.IsValid then TempFrame.LoadRequest(aRequest);
+      if (TempFrame <> nil) and TempFrame.IsValid then
+        TempFrame.LoadRequest(aRequest);
     end;
 end;
 
@@ -5692,7 +5718,8 @@ begin
   if Initialized then
     begin
       TempFrame := Browser.MainFrame;
-      if (TempFrame <> nil) and TempFrame.IsValid then Result := TempFrame.URL;
+      if (TempFrame <> nil) and TempFrame.IsValid then
+        Result := TempFrame.URL;
     end;
 end;
 
@@ -7697,6 +7724,16 @@ begin
     AudioMuted := not(AudioMuted);
 end;
 
+function TChromiumCore.doTryCloseBrowser: boolean;
+begin
+  if Initialized then
+    Result := Browser.Host.TryCloseBrowser
+   else
+    Result := True;
+
+  FTryingToCloseBrowser := False;
+end;
+
 procedure TChromiumCore.doEnableFocus;
 begin
   FCanFocus := True;

source/uCEFInterfaces.pas

@@ -507,6 +507,7 @@ type
     procedure doSetAudioMuted(aValue : boolean);
     procedure doToggleAudioMuted;
     procedure doEnableFocus;
+    function  doTryCloseBrowser : boolean;
     function  MustCreateAudioHandler : boolean;
     function  MustCreateCommandHandler : boolean;
     function  MustCreateLoadHandler : boolean;

source/uCEFTask.pas

@@ -197,6 +197,11 @@ type
       procedure Execute; override;
   end;
 
+  TCefTryCloseBrowserTask = class(TCefChromiumTask)
+    protected
+      procedure Execute; override;
+  end;
+
 implementation
 
 uses
@@ -677,4 +682,22 @@ begin
   end;
 end;
 
+
+// TCefTryCloseBrowserTask
+
+procedure TCefTryCloseBrowserTask.Execute;
+begin
+  try
+    try
+      if CanExecute then
+        IChromiumEvents(FEvents).doTryCloseBrowser;
+    except
+      on e : exception do
+        if CustomExceptionHandler('TCefTryCloseBrowserTask.Execute', e) then raise;
+    end;
+  finally
+    FEvents := nil;
+  end;
+end;
+
 end.

update_CEF4Delphi.json

@@ -2,7 +2,7 @@
   "UpdateLazPackages" : [
     {
       "ForceNotify" : true,
-      "InternalVersion" : 654,
+      "InternalVersion" : 655,
       "Name" : "cef4delphi_lazarus.lpk",
       "Version" : "128.4.9"
     }