Implement committed physical memory stats for Linux.

src/platform-nullos.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 317 matching lines @@
   return false;
 }
 
 
 bool VirtualMemory::Guard(void* address) {
   UNIMPLEMENTED();
   return false;
 }
 
 
+bool VirtualMemory::CommittedPhysicalSizeInRegion(
+    void* base, size_t size, size_t* physical) {
+  // TODO(alph): implement for the platform.
+  return false;
+}
+
+
 class Thread::PlatformData : public Malloced {
  public:
   PlatformData() {
     UNIMPLEMENTED();
   }
 
   void* pd_data_;
 };
 
 
@@ skipping 149 matching lines @@
   UNIMPLEMENTED();
 }
 
 
 void ProfileSampler::Stop() {
   UNIMPLEMENTED();
 }
 
 
 } }  // namespace v8::internal