Add swapBuffer call to SkGLContextHelper.

src/gpu/gl/win/SkNativeGLContext_win.cpp

 
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gl/SkNativeGLContext.h"
 #include "SkWGL.h"
@@ skipping 94 matching lines @@
     }
 
     return interface;
 }
 
 void SkNativeGLContext::makeCurrent() const {
     if (!wglMakeCurrent(fDeviceContext, fGlRenderContext)) {
         SkDebugf("Could not create rendering context.\n");
     }
 }
+
+void SkNativeGLContext::swapBuffers() const {
+    if (!SwapBuffers(fDeviceContext)) {
+        SkDebugf("Could not complete SwapBuffers.\n");
+    }
+}