[Isolates] Fix memory leaks in Isolate and Logger.

src/log.cc

 // Copyright 2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 330 matching lines @@
     heap_profiler_nesting_(0),
     log_(new Log(this)),
     is_initialized_(false),
     last_address_(NULL),
     prev_sp_(NULL),
     prev_function_(NULL),
     prev_to_(NULL),
     prev_code_(NULL) {
 }
 
+Logger::~Logger() {
+  delete log_;
+}
+
 #define DECLARE_LONG_EVENT(ignore1, long_name, ignore2) long_name,
 static const char* const kLongLogEventsNames[Logger::NUMBER_OF_LOG_EVENTS] = {
   LOG_EVENTS_AND_TAGS_LIST(DECLARE_LONG_EVENT)
 };
 #undef DECLARE_LONG_EVENT
 
 #define DECLARE_SHORT_EVENT(ignore1, ignore2, short_name) short_name,
 static const char* const
 kCompressedLogEventsNames[Logger::NUMBER_OF_LOG_EVENTS] = {
   LOG_EVENTS_AND_TAGS_LIST(DECLARE_SHORT_EVENT)
@@ skipping 1250 matching lines @@
   }
   // Otherwise, if the sliding state window computation has not been
   // started we do it now.
   if (sliding_state_window_ == NULL) {
     sliding_state_window_ = new SlidingStateWindow();
   }
 #endif
 }
 
 } }  // namespace v8::internal