Do not overwrite event logger when we explicitly have --log-timer-events.

src/api.cc

 // Copyright 2012 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.
 
 #include "src/api.h"
 
 #include <string.h>  // For memcpy, strlen.
 #ifdef V8_USE_ADDRESS_SANITIZER
 #include <sanitizer/asan_interface.h>
 #endif  // V8_USE_ADDRESS_SANITIZER
@@ skipping 6631 matching lines @@
   heap_statistics->total_heap_size_ = heap->CommittedMemory();
   heap_statistics->total_heap_size_executable_ =
       heap->CommittedMemoryExecutable();
   heap_statistics->total_physical_size_ = heap->CommittedPhysicalMemory();
   heap_statistics->used_heap_size_ = heap->SizeOfObjects();
   heap_statistics->heap_size_limit_ = heap->MaxReserved();
 }
 
 
 void Isolate::SetEventLogger(LogEventCallback that) {
+  // Do not overwrite the event logger if we want to log explicitly.
+  if (i::FLAG_log_timer_events) return;
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
   isolate->set_event_logger(that);
 }
 
 
 void Isolate::AddCallCompletedCallback(CallCompletedCallback callback) {
   if (callback == NULL) return;
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
   isolate->AddCallCompletedCallback(callback);
 }
@@ skipping 930 matching lines @@
   Isolate* isolate = reinterpret_cast<Isolate*>(info.GetIsolate());
   Address callback_address =
       reinterpret_cast<Address>(reinterpret_cast<intptr_t>(callback));
   VMState<EXTERNAL> state(isolate);
   ExternalCallbackScope call_scope(isolate, callback_address);
   callback(info);
 }
 
 
 } }  // namespace v8::internal