Store log messages in global activity tracker.

base/debug/activity_tracker.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Activity tracking provides a low-overhead method of collecting information
 // about the state of the application for analysis both while it is running
 // and after it has terminated unexpectedly. Its primary purpose is to help
 // locate reasons the browser becomes unresponsive by providing insight into
 // what all the various threads and processes are (or were) doing.
 
@@ skipping 524 matching lines @@
   // Type identifiers used when storing in persistent memory so they can be
   // identified during extraction; the first 4 bytes of the SHA1 of the name
   // is used as a unique integer. A "version number" is added to the base
   // so that, if the structure of that object changes, stored older versions
   // will be safely ignored. These are public so that an external process
   // can recognize records of this type within an allocator.
   enum : uint32_t {
     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,
   };
 
   // This is a thin wrapper around the thread-tracker's ScopedActivity that
   // accesses the global tracker to provide some of the information, notably
   // which thread-tracker to use. It is safe to create even if activity
   // tracking is not enabled.
   class BASE_EXPORT ScopedThreadActivity
@@ skipping 91 matching lines @@
   void ReleaseTrackerForCurrentThreadForTesting();
 
   // Gets a reference to memory for holding user-defined activity data. If
   // the reference is valid, it's memory will be returned. If not, then a
   // new reference will be created (and stored) and that memory returned.
   void* GetUserDataMemory(PersistentMemoryAllocator::Reference* reference);
 
   // 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_; }
 
  private:
   friend class ActivityTrackerTest;
 
   enum : int {
     // The maximum number of threads that can be tracked within a process. If
     // more than this number run concurrently, tracking of new ones may cease.
     kMaxThreadCount = 100,
@@ skipping 192 matching lines @@
   ScopedProcessWaitActivity(const void* program_counter,
                             const base::Process* process);
   DISALLOW_COPY_AND_ASSIGN(ScopedProcessWaitActivity);
 };
 #endif
 
 }  // namespace debug
 }  // namespace base
 
 #endif  // BASE_DEBUG_ACTIVITY_TRACKER_H_