[SHLWAPI][SDK] Support IUnknown_ShowBrowserBar (reactos#9161)

Implementing missing features...
JIRA issue: CORE-19278
- Implement
  IUnknown_ShowBrowserBar
  function.
- Modify shlwapi.spec.
- Add prototype into
  <shlwapi_undoc.h>.

Author: katahiromz

dll/win32/shlwapi/shlwapi.spec

@@ -536,7 +536,7 @@
 536 stdcall -noname IUnknown_QueryServicePropertyBag(ptr long ptr ptr)
 537 stdcall -noname SHBoolSystemParametersInfo(long ptr)
 538 stdcall -noname IUnknown_QueryServiceForWebBrowserApp(ptr ptr ptr)
-539 stub -noname IUnknown_ShowBrowserBar
+539 stdcall -noname IUnknown_ShowBrowserBar(ptr ptr long)
 540 stdcall -noname SHInvokeCommandOnContextMenu(ptr ptr ptr long str)
 541 stdcall -noname SHInvokeCommandsOnContextMenu(ptr ptr ptr long ptr long)
 542 stdcall -noname GetUIVersion()

dll/win32/shlwapi/utils.cpp

@@ -1011,6 +1011,29 @@ _AllocValueString(
     return S_OK;
 }
 
+/*************************************************************************
+ * IUnknown_ShowBrowserBar [SHLWAPI.539]
+ *
+ * @see IWebBrowser2
+ */
+EXTERN_C HRESULT WINAPI
+IUnknown_ShowBrowserBar(
+    _In_ IUnknown* punk,
+    _In_ REFGUID rguid,
+    _In_ BOOL bShow)
+{
+    CComPtr<IWebBrowser2> pWB2;
+    HRESULT hr = IUnknown_QueryServiceForWebBrowserApp(punk, IID_IWebBrowser2, (PVOID*)&pWB2);
+    if (FAILED(hr))
+        return hr;
+
+    WCHAR szGUID[40];
+    StringFromGUID2(rguid, szGUID, _countof(szGUID));
+
+    CComVariant varClsid(szGUID), varShow((bool)!!bShow), varSize;
+    return pWB2->ShowBrowserBar(&varClsid, &varShow, &varSize);
+}
+
 /*************************************************************************
  * PrettifyFileDescriptionW [SHLWAPI.492]
  *

sdk/include/reactos/shlwapi_undoc.h

@@ -81,6 +81,12 @@ NextPathW(
 #define NextPath NextPathA
 #endif
 
+HRESULT WINAPI
+IUnknown_ShowBrowserBar(
+    _In_ IUnknown* punk,
+    _In_ REFGUID rguid,
+    _In_ BOOL bShow);
+
 HRESULT WINAPI CLSIDFromStringWrap(_In_ LPCWSTR idstr, _Out_ CLSID *id);
 HMODULE WINAPI SHPinDllOfCLSID(REFIID refiid);
 HRESULT WINAPI IUnknown_QueryStatus(IUnknown *lpUnknown, REFGUID pguidCmdGroup, ULONG cCmds, OLECMD *prgCmds, OLECMDTEXT* pCmdText);