[profiler] Add extra CHECK to catch a crash in profiler.

src/profiler/profile-generator.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/profiler/profile-generator.h"
 
 #include "src/base/adapters.h"
 #include "src/debug/debug.h"
 #include "src/deoptimizer.h"
 #include "src/global-handles.h"
@@ skipping 746 matching lines @@
 
 CodeEntry* ProfileGenerator::FindEntry(void* address) {
   CodeEntry* entry = code_map_.FindEntry(reinterpret_cast<Address>(address));
   if (!entry) {
     RuntimeCallStats* rcs = isolate_->counters()->runtime_call_stats();
     void* start = reinterpret_cast<void*>(rcs);
     void* end = reinterpret_cast<void*>(rcs + 1);
     if (start <= address && address < end) {
       RuntimeCallCounter* counter =
           reinterpret_cast<RuntimeCallCounter*>(address);
+      CHECK(counter->name);
       entry = new CodeEntry(CodeEventListener::FUNCTION_TAG, counter->name,
                             CodeEntry::kEmptyNamePrefix, "native V8Runtime");
       code_map_.AddCode(reinterpret_cast<Address>(address), entry, 1);
     }
   }
   return entry;
 }
 
 CodeEntry* ProfileGenerator::EntryForVMState(StateTag tag) {
   switch (tag) {
     case GC:
       return CodeEntry::gc_entry();
     case JS:
     case COMPILER:
     // DOM events handlers are reported as OTHER / EXTERNAL entries.
     // To avoid confusing people, let's put all these entries into
     // one bucket.
     case OTHER:
     case EXTERNAL:
       return CodeEntry::program_entry();
     case IDLE:
       return CodeEntry::idle_entry();
     default: return NULL;
   }
 }
 
 }  // namespace internal
 }  // namespace v8