Add glDrawBuffer(s) to GrGLInterface

Review URL: http://codereview.appspot.com/4841046/



git-svn-id: http://skia.googlecode.com/svn/trunk@2032 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/src/mesa/GrGLDefaultInterface_mesa.cpp b/gpu/src/mesa/GrGLDefaultInterface_mesa.cpp
index e03c44e..56f2cf7 100644
--- a/gpu/src/mesa/GrGLDefaultInterface_mesa.cpp
+++ b/gpu/src/mesa/GrGLDefaultInterface_mesa.cpp
@@ -65,6 +65,8 @@
         gDefaultInterface.fDisableClientState = glDisableClientState;
         GR_GL_GET_PROC(DisableVertexAttribArray);
         gDefaultInterface.fDrawArrays = glDrawArrays;
+        gDefaultInterface.fDrawBuffer = glDrawBuffer;
+        GR_GL_GET_PROC(DrawBuffers);
         gDefaultInterface.fDrawElements = glDrawElements;
         gDefaultInterface.fEnable = glEnable;
         gDefaultInterface.fEnableClientState = glEnableClientState;