Add MemoryCoordinatorImpl

content/browser/memory/memory_monitor.cc

Index: content/browser/memory/memory_monitor.cc
diff --git a/content/browser/memory/memory_monitor.cc b/content/browser/memory/memory_monitor.cc
index 5e67c9cb5b30ad1bbbc7efeacabbe6b8586fce83..a9e168457df9f3a93972b4b80966682948e5c004 100644
--- a/content/browser/memory/memory_monitor.cc
+++ b/content/browser/memory/memory_monitor.cc
@@ -22,4 +22,12 @@ void MemoryMonitorDelegate::GetSystemMemoryInfo(
   base::GetSystemMemoryInfo(mem_info);
 }
 
+#if defined(OS_MACOSX)
+// TODO(bashi,bcwhite): Remove when memory monitor for mac is available.
+std::unique_ptr<MemoryMonitor> CreateMemoryMonitor() {
+  NOTREACHED();
+  return std::unique_ptr<MemoryMonitor>();
+}
+#endif
+
 }  // namespace content