Make mixed samples contingent on auxiliary extensions

include/gpu/gl/GrGLInterface.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrGLInterface_DEFINED
 #define GrGLInterface_DEFINED
 
@@ skipping 228 matching lines @@
         GLPtr<GrGLMapBufferProc> fMapBuffer;
         GLPtr<GrGLMapBufferRangeProc> fMapBufferRange;
         GLPtr<GrGLMapBufferSubDataProc> fMapBufferSubData;
         GLPtr<GrGLMapTexSubImage2DProc> fMapTexSubImage2D;
         GLPtr<GrGLMatrixLoadfProc> fMatrixLoadf;
         GLPtr<GrGLMatrixLoadIdentityProc> fMatrixLoadIdentity;
         GLPtr<GrGLPixelStoreiProc> fPixelStorei;
         GLPtr<GrGLPopGroupMarkerProc> fPopGroupMarker;
         GLPtr<GrGLPushGroupMarkerProc> fPushGroupMarker;
         GLPtr<GrGLQueryCounterProc> fQueryCounter;
+        GLPtr<GrGLRasterSamplesProc> fRasterSamples;
         GLPtr<GrGLReadBufferProc> fReadBuffer;
         GLPtr<GrGLReadPixelsProc> fReadPixels;
         GLPtr<GrGLRenderbufferStorageProc> fRenderbufferStorage;
 
         //  On OpenGL ES there are multiple incompatible extensions that add support for MSAA
         //  and ES3 adds MSAA support to the standard. On an ES3 driver we may still use the
         //  older extensions for performance reasons or due to ES3 driver bugs. We want the function
         //  that creates the GrGLInterface to provide all available functions and internally
         //  we will select among them. They all have a method called glRenderbufferStorageMultisample*.
         //  So we have separate function pointers for GL_IMG/EXT_multisampled_to_texture,
@@ skipping 100 matching lines @@
 #if GR_GL_PER_GL_FUNC_CALLBACK
     GrGLInterfaceCallbackProc fCallback;
     GrGLInterfaceCallbackData fCallbackData;
 #endif
 
     // This exists for internal testing.
     virtual void abandon() const {}
 };
 
 #endif