[WIP] Add SharedMemoryTracker to dump base::SharedMemory usage

base/BUILD.gn

Index: base/BUILD.gn
diff --git a/base/BUILD.gn b/base/BUILD.gn
index 82e9c8ab987551da3731838b09493b4708c48eae..5f64bf17e9d88864dbf4f6df6d3fe4672d90c901 100644
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -514,6 +514,8 @@ component("base") {
     "memory/shared_memory_mac.cc",
     "memory/shared_memory_nacl.cc",
     "memory/shared_memory_posix.cc",
+    "memory/shared_memory_tracker.cc",
+    "memory/shared_memory_tracker.h",
     "memory/shared_memory_win.cc",
     "memory/singleton.cc",
     "memory/singleton.h",
@@ -1649,13 +1651,6 @@ component("base") {
     sources += [ "power_monitor/power_monitor_device_source_posix.cc" ]
   }
 
-  if (is_posix && !is_mac && !is_nacl) {
-    sources += [
-      "memory/shared_memory_tracker.cc",
-      "memory/shared_memory_tracker.h",
-    ]
-  }
-
   if (!use_glib) {
     sources -= [
       "message_loop/message_pump_glib.cc",