0032433: Visualization, TKService - introduce Wasm_Window implementing Aspect_Window interface using Emscripten SDK

Introduced Wasm_Window implementing Aspect_Window interface.

Aspect_WindowInputListener has been extended by touch input callbacks (moved from AIS_ViewController),
which now implements redirection of single taps to UpdateMouseClick().

AIS_ViewController::FetchNavigationKeys() now requests more frames even if Delta is zero,
but navigation keys are pressed - indicated by a new flag AIS_WalkDelta::IsDefined().

Fixed missing implementation of Xw_Window::DisplayConnection() getter.
The property has been moved to the base class Aspect_Window.

Removed unused Aspect_Convert.hxx.

DRAWEXE targeting Wasm:
- added exposing of FS interface so that it is possible uploading/downloading files to/from emulated file system on JavaScript level;
- added printer redirecting messages to Module.printMessage callback accepting message gravity;
- Run_Appli() now skips std::cin when Module.noExitRuntime is set.

src/ViewerTest/ViewerTest_EventManager.hxx

@@ -22,6 +22,7 @@
 #include <TCollection_AsciiString.hxx>
 
 class AIS_InteractiveContext;
+class Aspect_Window;
 class V3d_View;
 
 DEFINE_STANDARD_HANDLE(ViewerTest_EventManager, Standard_Transient)
@@ -58,6 +59,9 @@ public:
   //! Destructor.
   Standard_EXPORT virtual ~ViewerTest_EventManager();
 
+  //! Setup or adjust window callbacks.
+  Standard_EXPORT static void SetupWindowCallbacks (const Handle(Aspect_Window)& theWin);
+
   //! Return interactive context.
   const Handle(AIS_InteractiveContext)& Context() const { return myCtx; }
 
@@ -75,6 +79,12 @@ public:
     myPickPntArgVec[2] = theArgZ;
   }
 
+  //! Handle mouse button click event.
+  Standard_EXPORT virtual bool UpdateMouseClick (const Graphic3d_Vec2i& thePoint,
+                                                  Aspect_VKeyMouse theButton,
+                                                  Aspect_VKeyFlags theModifiers,
+                                                  bool theIsDoubleClick) Standard_OVERRIDE;
+
   //! Handle mouse button press/release event.
   Standard_EXPORT virtual bool UpdateMouseButtons (const Graphic3d_Vec2i& thePoint,
                                                    Aspect_VKeyMouse theButtons,
@@ -138,6 +148,8 @@ private:
   Standard_Boolean myToPickPnt;
   Standard_Boolean myIsTmpContRedraw;
 
+  unsigned int     myUpdateRequests; //!< counter for unhandled update requests
+
 };
 
 #endif // _ViewerTest_EventManager_HeaderFile