Improve grammar in some comments.

base/memory/memory_pressure_monitor_chromeos.cc

 // Copyright 2014 The Chromium 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 "base/memory/memory_pressure_monitor_chromeos.h"
 
 #include <fcntl.h>
 #include <sys/select.h>
 
 #include "base/metrics/histogram_macros.h"
@@ skipping 68 matching lines @@
     int actual_fill_level,
     int moderate_threshold,
     int critical_threshold) {
   if (actual_fill_level < moderate_threshold)
     return MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE;
   return actual_fill_level < critical_threshold
              ? MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE
              : MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL;
 }
 
-// This function will be called less then once a second. It will check if
+// This function will be called less than once a second. It will check if
 // the kernel has detected a low memory situation.
 bool IsLowMemoryCondition(int file_descriptor) {
   fd_set fds;
   struct timeval tv;
 
   FD_ZERO(&fds);
   FD_SET(file_descriptor, &fds);
 
   tv.tv_sec = 0;
   tv.tv_usec = 0;
@@ skipping 173 matching lines @@
   return percentage;
 }
 
 void MemoryPressureMonitor::SetDispatchCallback(
     const DispatchCallback& callback) {
   dispatch_callback_ = callback;
 }
 
 }  // namespace chromeos
 }  // namespace base