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

gpu/command_buffer/service/context_state.cc

Index: gpu/command_buffer/service/context_state.cc
diff --git a/gpu/command_buffer/service/context_state.cc b/gpu/command_buffer/service/context_state.cc
index 0a3ff51599f30bf41907b27310640ed939bd194a..94192a6129b60afddd03bd3597aa5876f8b62f03 100644
--- a/gpu/command_buffer/service/context_state.cc
+++ b/gpu/command_buffer/service/context_state.cc
@@ -230,6 +230,11 @@ ContextState::ContextState(FeatureInfo* feature_info,
 ContextState::~ContextState() {
 }
 
+void ContextState::SetLineWidthBounds(GLfloat min, GLfloat max) {
+  line_width_min_ = min;
+  line_width_max_ = max;
+}
+
 void ContextState::RestoreTextureUnitBindings(
     GLuint unit, const ContextState* prev_state) const {
   DCHECK_LT(unit, texture_units.size());
@@ -297,6 +302,11 @@ void ContextState::RestoreUnpackState() const {
   }
 }
 
+void ContextState::DoLineWidth(GLfloat width) const {
+  glLineWidth(
+      std::min(std::max(width, line_width_min_), line_width_max_));
+}
+
 void ContextState::RestoreBufferBindings() const {
   if (vertex_attrib_manager.get()) {
     Buffer* element_array_buffer =