Add a basic Mojo app that initializes V8

mojo/apps/js/v8_environment.cc

+// Copyright 2013 The Chromium 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 "mojo/apps/js/v8_environment.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "mojo/public/system/macros.h"
+#include "v8/include/v8.h"
+
+namespace mojo {
+namespace apps {
+
+namespace {
+
+class ArrayBufferAllocator : public v8::ArrayBuffer::Allocator {
+  virtual void* Allocate(size_t length) MOJO_OVERRIDE {
+    return calloc(1, length);
+  }
+  virtual void* AllocateUninitialized(size_t length) MOJO_OVERRIDE {
+    return malloc(length);
+  }
+  virtual void Free(void* data, size_t length) MOJO_OVERRIDE {
+    free(data);
+  }
+};
+
+bool GenerateEntropy(unsigned char* buffer, size_t amount) {
+  // TODO(abarth): Mojo needs a source of entropy.
+  // https://code.google.com/p/chromium/issues/detail?id=316387
+  return false;
+}
+
+const char kFlags[] = "--use_strict --harmony";
+
+}
+
+void InitializeV8() {
+  v8::V8::SetArrayBufferAllocator(new ArrayBufferAllocator());
+  v8::V8::InitializeICU();
+  v8::V8::SetFlagsFromString(kFlags, strlen(kFlags));
+  v8::V8::SetEntropySource(&GenerateEntropy);
+  v8::V8::Initialize();
+}
+
+}  // namespace apps
+}  // mojo