Add reminder in the code to fix T-junctions

Change-Id: I52b112694f930e641f01fb78dc55412986023411
diff --git a/libs/hwui/OpenGLRenderer.cpp b/libs/hwui/OpenGLRenderer.cpp
index a20a88e..24784af 100644
--- a/libs/hwui/OpenGLRenderer.cpp
+++ b/libs/hwui/OpenGLRenderer.cpp
@@ -724,6 +724,8 @@
         return;
     }
 
+    // TODO: See LayerRenderer.cpp::generateMesh() for important
+    //       information about this implementation
     if (!layer->region.isEmpty()) {
         size_t count;
         const android::Rect* rects = layer->region.getArray(&count);