SW backend for viewer on Windows

tools/viewer/sk_app/win/Window_win.cpp

 /*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
 #include "Window_win.h"
 
 #include <tchar.h>
@@ skipping 252 matching lines @@
 }
 
 void Window_win::show() {
     ShowWindow(fHWnd, SW_SHOW);
 }
 
 
 bool Window_win::attach(BackendType attachType, const DisplayParams& params) {
     switch (attachType) {
         case kNativeGL_BackendType:
-        default:
             fWindowContext = window_context_factory::NewGLForWin(fHWnd, params);
             break;
+        case kRaster_BackendType:
+            fWindowContext = window_context_factory::NewRasterForWin(fHWnd, params);
+            break;
 #ifdef SK_VULKAN
         case kVulkan_BackendType:
             fWindowContext = window_context_factory::NewVulkanForWin(fHWnd, params);
             break;
 #endif
     }
 
     return (SkToBool(fWindowContext));
 }
 
 void Window_win::onInval() {
     InvalidateRect(fHWnd, nullptr, false);
 }
 
 }   // namespace sk_app