Rename OS-specific MemoryPressureMonitor implementations.

base/BUILD.gn

Index: base/BUILD.gn
diff --git a/base/BUILD.gn b/base/BUILD.gn
index 2170520185d2cf813a8159159305b64a280fbb6c..de282cfe35d6ffa89c414156b6e02725e5d8d6f0 100644
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -167,8 +167,8 @@ component("base") {
     "callback_internal.cc",
     "callback_internal.h",
     "cancelable_callback.h",
-    "chromeos/memory_pressure_monitor_chromeos.cc",
-    "chromeos/memory_pressure_monitor_chromeos.h",
+    "chromeos/memory_pressure_monitor.cc",
+    "chromeos/memory_pressure_monitor.h",
     "command_line.cc",
     "command_line.h",
     "compiler_specific.h",
@@ -287,8 +287,8 @@ component("base") {
     "mac/mac_util.mm",
     "mac/mach_logging.cc",
     "mac/mach_logging.h",
-    "mac/memory_pressure_monitor_mac.cc",
-    "mac/memory_pressure_monitor_mac.h",
+    "mac/memory_pressure_monitor.cc",
+    "mac/memory_pressure_monitor.h",
     "mac/objc_property_releaser.h",
     "mac/objc_property_releaser.mm",
     "mac/os_crash_dumps.cc",
@@ -1098,7 +1098,7 @@ test("base_unittests") {
     "callback_unittest.cc",
     "callback_unittest.nc",
     "cancelable_callback_unittest.cc",
-    "chromeos/memory_pressure_monitor_chromeos_unittest.cc",
+    "chromeos/memory_pressure_monitor_unittest.cc",
     "command_line_unittest.cc",
     "containers/adapters_unittest.cc",
     "containers/hash_tables_unittest.cc",