Add swapBuffer call to SkGLContextHelper.

src/gpu/gl/mac/SkNativeGLContext_mac.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 "AvailabilityMacros.h"
 
@@ skipping 21 matching lines @@
     }
 }
 
 const GrGLInterface* SkNativeGLContext::createGLContext() {
     SkASSERT(NULL == fContext);
 
     CGLPixelFormatAttribute attributes[] = {
 #if MAC_OS_X_VERSION_10_7
         kCGLPFAOpenGLProfile, (CGLPixelFormatAttribute) kCGLOGLPVersion_3_2_Core,
 #endif
+        kCGLPFADoubleBuffer,
         (CGLPixelFormatAttribute)0
     };
     CGLPixelFormatObj pixFormat;
     GLint npix;
 
     CGLChoosePixelFormat(attributes, &pixFormat, &npix);
 
     if (NULL == pixFormat) {
         SkDebugf("CGLChoosePixelFormat failed.");
         return NULL;
@@ skipping 15 matching lines @@
         this->destroyGLContext();
         return NULL;
     }
 
     return interface;
 }
 
 void SkNativeGLContext::makeCurrent() const {
     CGLSetCurrentContext(fContext);
 }
+
+void SkNativeGLContext::swapBuffers() const {
+    CGLFlushDrawable(fContext);
+}