Add GrEllipseEdgeEffect

src/gpu/GrTextContext.cpp

Index: src/gpu/GrTextContext.cpp
===================================================================
--- src/gpu/GrTextContext.cpp	(revision 8091)
+++ src/gpu/GrTextContext.cpp	(working copy)
@@ -19,6 +19,9 @@
 #include "SkStrokeRec.h"
 
 enum {
+    // glyph rendering shares this stage with edge rendering 
+    // (kEdgeEffectStage in GrContext) && SW path rendering 
+    // (kPathMaskStage in GrSWMaskHelper)
     kGlyphMaskStage = GrPaint::kTotalStages,
 };