Add glReadBuffer to GrGLInterface.

Review URL: http://codereview.appspot.com/4841048/





git-svn-id: http://skia.googlecode.com/svn/trunk@2034 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/include/GrGLInterface.h b/gpu/include/GrGLInterface.h
index 63ebca5..0e0c566 100644
--- a/gpu/include/GrGLInterface.h
+++ b/gpu/include/GrGLInterface.h
@@ -136,6 +136,7 @@
     typedef GrGLvoid (GR_GL_FUNCTION_TYPE *GrGLMatrixModeProc)(GrGLenum mode);
     typedef GrGLvoid (GR_GL_FUNCTION_TYPE *GrGLPixelStoreiProc)(GrGLenum pname, GrGLint param);
     typedef GrGLvoid (GR_GL_FUNCTION_TYPE *GrGLPointSizeProc)(GrGLfloat size);
+    typedef GrGLvoid (GR_GL_FUNCTION_TYPE *GrGLReadBufferProc)(GrGLenum src);
     typedef GrGLvoid (GR_GL_FUNCTION_TYPE *GrGLReadPixelsProc)(GrGLint x, GrGLint y, GrGLsizei width, GrGLsizei height, GrGLenum format, GrGLenum type, GrGLvoid* pixels);
     typedef GrGLvoid (GR_GL_FUNCTION_TYPE *GrGLScissorProc)(GrGLint x, GrGLint y, GrGLsizei width, GrGLsizei height);
     typedef GrGLvoid (GR_GL_FUNCTION_TYPE *GrGLShadeModelProc)(GrGLenum mode);
@@ -291,6 +292,7 @@
     GrGLMatrixModeProc fMatrixMode;
     GrGLPixelStoreiProc fPixelStorei;
     GrGLPointSizeProc fPointSize;
+    GrGLReadBufferProc fReadBuffer;
     GrGLReadPixelsProc fReadPixels;
     GrGLScissorProc fScissor;
     GrGLShadeModelProc fShadeModel;