Fix CPU profiler crash in start / stop sequence when non-existent name is passed

src/profile-generator.h

 // Copyright 2010 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 261 matching lines @@
 class CpuProfilesCollection {
  public:
   CpuProfilesCollection();
   ~CpuProfilesCollection();
 
   bool StartProfiling(const char* title, unsigned uid);
   bool StartProfiling(String* title, unsigned uid);
   CpuProfile* StopProfiling(int security_token_id,
                             const char* title,
                             double actual_sampling_rate);
-  CpuProfile* StopProfiling(int security_token_id,
-                            String* title,
-                            double actual_sampling_rate);
   List<CpuProfile*>* Profiles(int security_token_id);
   const char* GetName(String* name) {
     return function_and_resource_names_.GetName(name);
   }
   CpuProfile* GetProfile(int security_token_id, unsigned uid);
-  inline bool is_last_profile();
+  bool IsLastProfile(const char* title);
 
   CodeEntry* NewCodeEntry(Logger::LogEventsAndTags tag,
                           String* name, String* resource_name, int line_number);
   CodeEntry* NewCodeEntry(Logger::LogEventsAndTags tag, const char* name);
   CodeEntry* NewCodeEntry(Logger::LogEventsAndTags tag,
                           const char* name_prefix, String* name);
   CodeEntry* NewCodeEntry(Logger::LogEventsAndTags tag, int args_count);
   CodeEntry* NewCodeEntry(int security_token_id);
 
   // Called from profile generator thread.
@@ skipping 645 matching lines @@
   friend class IndexedReferencesExtractor;
 
   DISALLOW_COPY_AND_ASSIGN(HeapSnapshotGenerator);
 };
 
 } }  // namespace v8::internal
 
 #endif  // ENABLE_LOGGING_AND_PROFILING
 
 #endif  // V8_PROFILE_GENERATOR_H_