Revert of Make the Sk GL context class an abstract base class

src/gpu/gl/mesa/SkMesaGLContext.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/osmesa.h>
 
 #include "gl/SkMesaGLContext.h"
 #include "gl/GrGLDefines.h"
 
+SkMesaGLContext::AutoContextRestore::AutoContextRestore() {
+    fOldContext = (Context)OSMesaGetCurrentContext();
+    if (fOldContext) {
+        OSMesaGetColorBuffer((OSMesaContext)fOldContext,
+                              &fOldWidth, &fOldHeight,
+                              &fOldFormat, &fOldImage);
+    }
+}
+
+SkMesaGLContext::AutoContextRestore::~AutoContextRestore() {
+    if (fOldContext) {
+        OSMesaMakeCurrent((OSMesaContext)fOldContext, fOldImage,
+                          fOldFormat, fOldWidth, fOldHeight);
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
 SkMesaGLContext::SkMesaGLContext()
     : fContext(static_cast<Context>(NULL))
     , fImage(NULL) {
     GR_STATIC_ASSERT(sizeof(Context) == sizeof(OSMesaContext));
 }
 
 SkMesaGLContext::~SkMesaGLContext() {
     this->destroyGLContext();
 }
 
@@ skipping 61 matching lines @@
 void SkMesaGLContext::makeCurrent() const {
     if (fContext) {
         if (!OSMesaMakeCurrent((OSMesaContext)fContext, fImage,
                                GR_GL_UNSIGNED_BYTE, gBOGUS_SIZE, gBOGUS_SIZE)) {
             SkDebugf("Could not make MESA context current.");
         }
     }
 }
 
 void SkMesaGLContext::swapBuffers() const { }