fix --show-composited-layer-borders on Mac

gpu/command_buffer/service/context_state.h

Index: gpu/command_buffer/service/context_state.h
diff --git a/gpu/command_buffer/service/context_state.h b/gpu/command_buffer/service/context_state.h
index 2378eeb3906693caec6f0b98b451a2b5eeedc1c9..e22faa61d0c881a3d315416c1b813c519ac94cc9 100644
--- a/gpu/command_buffer/service/context_state.h
+++ b/gpu/command_buffer/service/context_state.h
@@ -166,6 +166,8 @@ struct GPU_EXPORT ContextState {
 
   void Initialize();
 
+  void SetLineWidthBounds(GLfloat min, GLfloat max);
+
   void SetIgnoreCachedStateForTest(bool ignore) {
     ignore_cached_state = ignore;
   }
@@ -192,6 +194,7 @@ struct GPU_EXPORT ContextState {
 
   void PushTextureDecompressionUnpackState() const;
   void RestoreUnpackState() const;
+  void DoLineWidth(GLfloat width) const;
 
   // Helper for getting cached state.
   bool GetStateAsGLint(
@@ -348,6 +351,9 @@ struct GPU_EXPORT ContextState {
   // the highest 2 bits for location (max_vertex_attribs - 1).
   std::vector<uint32_t> generic_attrib_base_type_mask_;
 
+  GLfloat line_width_min_ = 0.0f;
+  GLfloat line_width_max_ = 1.0f;
+
   FeatureInfo* feature_info_;
   std::unique_ptr<ErrorState> error_state_;
 };