improve grammar in comment

src/heap/gc-tracer.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/heap/gc-tracer.h"
 
 #include "src/counters.h"
 #include "src/heap/heap-inl.h"
 #include "src/isolate.h"
 
@@ skipping 316 matching lines @@
                                 size_t new_space_counter_bytes,
                                 size_t old_generation_counter_bytes) {
   if (allocation_time_ms_ == 0) {
     // It is the first sample.
     allocation_time_ms_ = current_ms;
     new_space_allocation_counter_bytes_ = new_space_counter_bytes;
     old_generation_allocation_counter_bytes_ = old_generation_counter_bytes;
     return;
   }
   // This assumes that counters are unsigned integers so that the subtraction
-  // below works even if the new counter is less then the old counter.
+  // below works even if the new counter is less than the old counter.
   size_t new_space_allocated_bytes =
       new_space_counter_bytes - new_space_allocation_counter_bytes_;
   size_t old_generation_allocated_bytes =
       old_generation_counter_bytes - old_generation_allocation_counter_bytes_;
   double duration = current_ms - allocation_time_ms_;
   allocation_time_ms_ = current_ms;
   new_space_allocation_counter_bytes_ = new_space_counter_bytes;
   old_generation_allocation_counter_bytes_ = old_generation_counter_bytes;
   allocation_duration_since_gc_ += duration;
   new_space_allocation_in_bytes_since_gc_ += new_space_allocated_bytes;
@@ skipping 465 matching lines @@
   return sum / recorded_survival_ratios_.Count();
 }
 
 bool GCTracer::SurvivalEventsRecorded() const {
   return recorded_survival_ratios_.Count() > 0;
 }
 
 void GCTracer::ResetSurvivalEvents() { recorded_survival_ratios_.Reset(); }
 }  // namespace internal
 }  // namespace v8