Even without --trace-gc dump the last few GC messages on OOM

src/heap/gc-tracer.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_GC_TRACER_H_
 #define V8_HEAP_GC_TRACER_H_
 
 #include "src/base/platform/platform.h"
 
 namespace v8 {
@@ skipping 402 matching lines @@
 
  private:
   // Print one detailed trace line in name=value format.
   // TODO(ernstm): Move to Heap.
   void PrintNVP() const;
 
   // Print one trace line.
   // TODO(ernstm): Move to Heap.
   void Print() const;
 
+  // Prints a line and also adds it to the heap's ring buffer so that
+  // it can be included in later crash dumps.
+  void Output(const char* format, ...) const;
+
   // Compute the mean duration of the events in the given ring buffer.
   double MeanDuration(const EventBuffer& events) const;
 
   // Compute the max duration of the events in the given ring buffer.
   double MaxDuration(const EventBuffer& events) const;
 
   void ClearMarkCompactStatistics() {
     cumulative_incremental_marking_steps_ = 0;
     cumulative_incremental_marking_bytes_ = 0;
     cumulative_incremental_marking_duration_ = 0;
@@ skipping 74 matching lines @@
 
   // Counts how many tracers were started without stopping.
   int start_counter_;
 
   DISALLOW_COPY_AND_ASSIGN(GCTracer);
 };
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_GC_TRACER_H_