Implement committed physical memory stats for Linux.

src/platform-win32.cc

Index: src/platform-win32.cc
diff --git a/src/platform-win32.cc b/src/platform-win32.cc
index 65d31a94f9174c23e72ad0a26e199ef0deda29e2..5e4dcf5850eb7ee451cd3c80cdbace39b9e9cc97 100644
--- a/src/platform-win32.cc
+++ b/src/platform-win32.cc
@@ -1551,6 +1551,12 @@ bool VirtualMemory::ReleaseRegion(void* base, size_t size) {
 }
 
 
+bool VirtualMemory::HasLazyCommits() {
+  // TODO(alph): implement for the platform.
+  return false;
+}
+
+
 // ----------------------------------------------------------------------------
 // Win32 thread support.