Introduce skeleton of taskbar button feature.

- Add classes: wxTaskBarButton and wxTaskBarButtonImpl.
- New interface in wxTopLevelWindowMSW to get its wxTaskBarButton:
    MSWGetTaskBarButton.
- A simple sample and build files under msvc.

Author: Chaobin Zhang

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77572 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/taskbarbutton.cpp

@@ -0,0 +1,63 @@
+/////////////////////////////////////////////////////////////////////////////
+// Name:        src/msw/taskbarbutton.cpp
+// Purpose:     Implements wxTaskbarButtonImpl class for manipulating buttons on
+//              the Windows taskbar.
+// Author:      Chaobin Zhang <zhchbin@gmail.com>
+// Created:     2014-06-01
+// Copyright:   (c) 2014 wxWidgets development team
+// Licence:     wxWindows licence
+/////////////////////////////////////////////////////////////////////////////
+
+#include "wx/wxprec.h"
+
+#ifdef __BORLANDC__
+    #pragma hdrstop
+#endif
+
+#if wxUSE_TASKBARBUTTON
+
+#include "wx/msw/wrapshl.h"
+#include "wx/msw/private.h"
+#include "wx/taskbarbutton.h"
+
+#include <Shobjidl.h>
+
+wxTaskBarButtonImpl::wxTaskBarButtonImpl(WXWidget parent) : m_hwnd(parent)
+{
+    HRESULT hr = CoCreateInstance
+                 (
+                    CLSID_TaskbarList,
+                    NULL,
+                    CLSCTX_ALL,
+                    IID_ITaskbarList3,
+                    reinterpret_cast<void **>(&m_taskbarList)
+                 );
+    if ( FAILED(hr) )
+    {
+        wxLogApiError(wxT("CoCreateInstance(CLSID_TaskbarButtonList)"), hr);
+        return;
+    }
+
+    hr = m_taskbarList->HrInit();
+    if ( FAILED(hr) )
+    {
+        wxLogApiError(wxT("ITaskbarButtonList3::Init"), hr);
+        return;
+    }
+}
+
+wxTaskBarButtonImpl::~wxTaskBarButtonImpl()
+{
+    if ( m_taskbarList )
+      m_taskbarList->Release();
+}
+
+void wxTaskBarButtonImpl::SetProgressValue(int value)
+{
+    wxCHECK_RET( value >= 0 && value <= 100,
+                 wxT("Invalid value, must be in the range of [0, 100].") );
+
+    m_taskbarList->SetProgressValue(m_hwnd, value, 100);
+}
+
+#endif // wxUSE_TASKBARBUTTON