[memory-infra] Log reasons for memory dump failure

base/trace_event/memory_dump_manager.h

Index: base/trace_event/memory_dump_manager.h
diff --git a/base/trace_event/memory_dump_manager.h b/base/trace_event/memory_dump_manager.h
index fd2226ae6c7e7b69db119b56cce22f52512f5807..77f1f54eb4a7548666e927e5d25738ea80e0e156 100644
--- a/base/trace_event/memory_dump_manager.h
+++ b/base/trace_event/memory_dump_manager.h
@@ -40,6 +40,7 @@ class MemoryDumpSessionState;
 class BASE_EXPORT MemoryDumpManager : public TraceLog::EnabledStateObserver {
  public:
   static const char* const kTraceCategory;
+  static const char* const kMemoryInfraDumpLogName;

[Primiano Tucci (use gerrit), 2016/06/09 09:51:22]

s/kMemoryInfraDumpLogName/kLogPrefix/

This is already in MemoryDumpManager scope, MemoryInfra seems reundant here in
the constant name.

[petrcermak, 2016/06/09 09:58:30]

Done. Note that since the constant is now called a "prefix", I changed it to
start with an uppercase letter.

 
   // This value is returned as the tracing id of the child processes by
   // GetTracingProcessId() when tracing is not enabled.