user32: Implement InternalGetWindowIcon().

dlls/user32/user32.spec

@@ -445,6 +445,7 @@
 @ stdcall InsertMenuItemA(long long long ptr)
 @ stdcall InsertMenuItemW(long long long ptr)
 @ stdcall InsertMenuW(long long long long ptr)
+@ stdcall InternalGetWindowIcon(ptr long)
 @ stdcall InternalGetWindowText(long ptr long)
 @ stdcall IntersectRect(ptr ptr ptr)
 @ stdcall InvalidateRect(long ptr long)

dlls/user32/win.c

@@ -4369,3 +4369,50 @@ BOOL WINAPI SetWindowCompositionAttribute(HWND hwnd, void *data)
     SetLastError(ERROR_CALL_NOT_IMPLEMENTED);
     return FALSE;
 }
+
+/***********************************************************************
+ *              InternalGetWindowIcon   (USER32.@)
+ */
+HICON WINAPI InternalGetWindowIcon( HWND hwnd, UINT type )
+{
+    WND *win = WIN_GetPtr( hwnd );
+    HICON ret;
+
+    TRACE( "hwnd %p, type %#x\n", hwnd, type );
+
+    if (!win)
+    {
+        SetLastError( ERROR_INVALID_WINDOW_HANDLE );
+        return 0;
+    }
+    if (win == WND_OTHER_PROCESS || win == WND_DESKTOP)
+    {
+        if (IsWindow( hwnd )) FIXME( "not supported on other process window %p\n", hwnd );
+        return 0;
+    }
+
+    switch (type)
+    {
+        case ICON_BIG:
+            ret = win->hIcon;
+            if (!ret) ret = (HICON)GetClassLongPtrW( hwnd, GCLP_HICON );
+            break;
+
+        case ICON_SMALL:
+        case ICON_SMALL2:
+            ret = win->hIconSmall ? win->hIconSmall : win->hIconSmall2;
+            if (!ret) ret = (HICON)GetClassLongPtrW( hwnd, GCLP_HICONSM );
+            if (!ret) ret = (HICON)GetClassLongPtrW( hwnd, GCLP_HICON );
+            break;
+
+        default:
+            SetLastError( ERROR_INVALID_PARAMETER );
+            WIN_ReleasePtr( win );
+            return 0;
+    }
+
+    if (!ret) ret = LoadIconW( 0, (const WCHAR *)IDI_APPLICATION );
+
+    WIN_ReleasePtr( win );
+    return CopyIcon( ret );
+}