Rename OS-specific MemoryPressureMonitor implementations.

chrome/browser/chromeos/memory/oom_priority_manager.cc

Index: chrome/browser/chromeos/memory/oom_priority_manager.cc
diff --git a/chrome/browser/chromeos/memory/oom_priority_manager.cc b/chrome/browser/chromeos/memory/oom_priority_manager.cc
index 38e2dafe2a4968774e77588de12890ed2601ac4d..4d3969b54ba2e57e5a28de8feeec3d69acaabc4c 100644
--- a/chrome/browser/chromeos/memory/oom_priority_manager.cc
+++ b/chrome/browser/chromeos/memory/oom_priority_manager.cc
@@ -512,9 +512,8 @@ void OomPriorityManager::Observe(int type,
         // driven MemoryPressureMonitor will continue to produce timed events
         // on top. So the longer the cleanup phase takes, the more tabs will
         // get discarded in parallel.
-        base::MemoryPressureMonitorChromeOS* monitor =
-            static_cast<base::MemoryPressureMonitorChromeOS*>(
-                base::MemoryPressureMonitor::Get());
+        base::chromeos::MemoryPressureMonitor* monitor =
+            base::chromeos::MemoryPressureMonitor::Get();
         if (monitor)
           monitor->ScheduleEarlyCheck();
       }