"interface" is defined in Windows headers, so undef it in GrGLCaps so we don't have a name collision

src/gpu/gl/GrGLCaps.h

Index: src/gpu/gl/GrGLCaps.h
diff --git a/src/gpu/gl/GrGLCaps.h b/src/gpu/gl/GrGLCaps.h
index 7f722f912d970f847baf03cc334a12dd3ef8f13e..ccf04fd7ba5a3d668ef5d2671d0defc5af6ea6b6 100644
--- a/src/gpu/gl/GrGLCaps.h
+++ b/src/gpu/gl/GrGLCaps.h
@@ -114,7 +114,7 @@ public:
      * Initializes the GrGLCaps to the set of features supported in the current
      * OpenGL context accessible via ctxInfo.
      */
-    bool init(const GrGLContextInfo& ctxInfo, const GrGLInterface* interface);
+    bool init(const GrGLContextInfo& ctxInfo, const GrGLInterface* glInterface);
 
     /**
      * Call to note that a color config has been verified as a valid color