Speed-up 'new TypedArray(arrayLike)'.

src/d8.cc

 // Copyright 2012 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 1544 matching lines @@
   fake_argv[2] = strdup("--trace-hydrogen-file=hydrogen.cfg");
   v8::V8::SetFlagsFromCommandLine(&fake_argc, fake_argv, false);
   free(fake_argv[1]);
   delete[] fake_argv;
 }
 #endif
 
 
 class ShellArrayBufferAllocator : public v8::ArrayBuffer::Allocator {
  public:
-  virtual void* Allocate(size_t length) { return malloc(length); }
+  virtual void* Allocate(size_t length) {
+    void* result = malloc(length);
+    memset(result, 0, length);
+    return result;
+  }
+  virtual void* AllocateUninitialized(size_t length) {
+    return malloc(length);
+  }
   virtual void Free(void* data) { free(data); }
 };
 
 
 int Shell::Main(int argc, char* argv[]) {
   if (!SetOptions(argc, argv)) return 1;
   v8::V8::InitializeICU();
 #ifndef V8_SHARED
   i::FLAG_harmony_array_buffer = true;
   i::FLAG_harmony_typed_arrays = true;
@@ skipping 71 matching lines @@
 }
 
 }  // namespace v8
 
 
 #ifndef GOOGLE3
 int main(int argc, char* argv[]) {
   return v8::Shell::Main(argc, argv);
 }
 #endif