Generate globally (cross-process) unique IDs for memory tracing dumps

base/trace_event/memory_dump_manager.cc

Index: base/trace_event/memory_dump_manager.cc
diff --git a/base/trace_event/memory_dump_manager.cc b/base/trace_event/memory_dump_manager.cc
index 8b2d930a4bc5ab1e09b0f4295910eff07d474a53..10a842ca19245dbedd9dde77572c1c4ae622afb4 100644
--- a/base/trace_event/memory_dump_manager.cc
+++ b/base/trace_event/memory_dump_manager.cc
@@ -106,9 +106,8 @@ void MemoryDumpManager::RequestDumpPoint(DumpPointType dump_point_type) {
   if (!UNLIKELY(subtle::NoBarrier_Load(&memory_tracing_enabled_)))
     return;
 
-  // TODO(primiano): Make guid actually unique (cross-process) by hashing it
-  // with the PID. See crbug.com/462931 for details.
-  const uint64 guid = g_next_guid.GetNext();
+  const uint64 guid = base::trace_event::TraceLog::GetInstance()->HashEventId(

[Primiano Tucci (use gerrit), 2015/04/13 22:13:58]

nit: no need for base::trace_event as you are already in the namespace

+      g_next_guid.GetNext());
   CreateLocalDumpPoint(dump_point_type, guid);
 }