Fix external snapshot reading

src/natives-external.cc

 // 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.
 
 #include "src/natives.h"
 
 #include "src/base/logging.h"
 #include "src/list.h"
 #include "src/list-inl.h"
 #include "src/snapshot-source-sink.h"
@@ skipping 16 matching lines @@
 
   int GetBuiltinsCount() { return native_names_.length(); }
   int GetDebuggerCount() { return debugger_count_; }
   Vector<const char> GetScriptName(int index) { return native_names_[index]; }
   Vector<const char> GetRawScriptSource(int index) {
     return native_source_[index];
   }
 
   int GetIndex(const char* name) {
     for (int i = 0; i < native_names_.length(); ++i) {
-      if (strcmp(name, native_names_[i].start()) == 0) {
+      int native_name_length = native_names_[i].length();
+      if ((static_cast<int>(strlen(name)) == native_name_length) &&
+          (strncmp(name, native_names_[i].start(), native_name_length) == 0)) {
         return i;
       }
     }
     DCHECK(false);
     return -1;
   }
 
   int GetRawScriptsSize() {
     DCHECK(false);  // Used for compression. Doesn't really make sense here.
     return 0;
@@ skipping 139 matching lines @@
 
 // The compiler can't 'see' all uses of the static methods and hence
 // my chose to elide them. This we'll explicitly instantiate these.
 template class NativesCollection<CORE>;
 template class NativesCollection<EXPERIMENTAL>;
 template class NativesCollection<D8>;
 template class NativesCollection<TEST>;
 
 }  // namespace v8::internal
 }  // namespace v8