[tracing] Introduce BACKGROUND mode in MemoryInfra

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 817768afedd886a41db3b62cd5130ecf9530610e..49f2e23eb642a0ac01d1b22dc0308d2fd4f3b732 100644
--- a/base/trace_event/memory_dump_manager.h
+++ b/base/trace_event/memory_dump_manager.h
@@ -18,7 +18,6 @@
 #include "base/memory/ref_counted.h"
 #include "base/memory/singleton.h"
 #include "base/synchronization/lock.h"
-#include "base/timer/timer.h"
 #include "base/trace_event/memory_dump_request_args.h"
 #include "base/trace_event/process_memory_dump.h"
 #include "base/trace_event/trace_event.h"
@@ -146,6 +145,7 @@ class BASE_EXPORT MemoryDumpManager : public TraceLog::EnabledStateObserver {
   friend struct DefaultSingletonTraits<MemoryDumpManager>;
   friend class MemoryDumpManagerDelegate;
   friend class MemoryDumpManagerTest;
+  class PeriodicGlobalDumpInvokeHelper;

[Primiano Tucci (use gerrit), 2016/05/26 17:20:53]

I think just PeriodicDumpHelper is enough (which also matches the name of the
variable below)

[ssid, 2016/05/26 22:12:54]

I think after including start and stop it is more like PeriodicGlobalDumpTimer.
Global because it says it is a global timer not per process.

Also declared it here since test needs isRunning function.

 
   // Descriptor used to hold information about registered MDPs.
   // Some important considerations about lifetime of this object:
@@ -200,6 +200,9 @@ class BASE_EXPORT MemoryDumpManager : public TraceLog::EnabledStateObserver {
     // Flagged either by the auto-disable logic or during unregistration.
     bool disabled;
 
+    // True if the dump provider is not whitelited for background mode.

[Primiano Tucci (use gerrit), 2016/05/26 17:20:53]

nit: whitelisted

[ssid, 2016/05/26 22:12:54]

Done.

+    const bool disabled_for_background_mode;

[Primiano Tucci (use gerrit), 2016/05/26 17:20:53]

in order to make this less confusing (initially I thought "why we have disabled
and disabled_for_background"?) I think this should really be named:
whitelisted_for_background_mode;

[ssid, 2016/05/26 22:12:54]

Done thanks

+
    private:
     friend class base::RefCountedThreadSafe<MemoryDumpProviderInfo>;
     ~MemoryDumpProviderInfo();
@@ -325,7 +328,7 @@ class BASE_EXPORT MemoryDumpManager : public TraceLog::EnabledStateObserver {
   subtle::AtomicWord memory_tracing_enabled_;
 
   // For time-triggered periodic dumps.
-  RepeatingTimer periodic_dump_timer_;
+  std::unique_ptr<PeriodicGlobalDumpInvokeHelper> periodic_dump_helper_;
 
   // Thread used for MemoryDumpProviders which don't specify a task runner
   // affinity.