Store log messages in global activity tracker.

base/debug/activity_tracker.h

Index: base/debug/activity_tracker.h
diff --git a/base/debug/activity_tracker.h b/base/debug/activity_tracker.h
index a3a9419c7ab1eb01a6edc0f9f4bab0bb72db5b7c..1767ef41e660e6dc9ac55716d9c730d8c93a10ad 100644
--- a/base/debug/activity_tracker.h
+++ b/base/debug/activity_tracker.h
@@ -542,6 +542,7 @@ class BASE_EXPORT GlobalActivityTracker {
     kTypeIdActivityTracker = 0x5D7381AF + 3,   // SHA1(ActivityTracker) v3
     kTypeIdUserDataRecord = 0x615EDDD7 + 1,    // SHA1(UserDataRecord) v1
     kTypeIdGlobalDataRecord = 0xAFE61ABE + 1,  // SHA1(GlobalDataRecord) v1
+    kTypeIdGlobalLogMessage = 0x4CF434F9 + 1,  // SHA1(GlobalLogMessage) v1
 
     kTypeIdActivityTrackerFree = ~kTypeIdActivityTracker,
     kTypeIdUserDataRecordFree = ~kTypeIdUserDataRecord,
@@ -653,6 +654,10 @@ class BASE_EXPORT GlobalActivityTracker {
   // Releases memory for user-defined activity data.
   void ReleaseUserDataMemory(PersistentMemoryAllocator::Reference* reference);
 
+  // Records a log message. The current implementation does NOT recycle these
+  // only store critical messages such as FATAL ones.

[manzagop (departed), 2016/12/02 20:08:09]

nit for your next cl: can you mention this is best effort on there being space
available?

+  void RecordLogMessage(StringPiece message);
+
   // Accesses the global data record for storing arbitrary key/value pairs.
   ActivityUserData& user_data() { return user_data_; }