Revert of Revert of Add AwAssets into android_webview/native/public

android_webview/native/public/aw_assets.cc

Index: android_webview/native/public/aw_assets.cc
diff --git a/android_webview/native/public/aw_assets.cc b/android_webview/native/public/aw_assets.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e13d04e1165a362809993581826161d1476f7e3f
--- /dev/null
+++ b/android_webview/native/public/aw_assets.cc
@@ -0,0 +1,55 @@
+// Copyright 2014 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 <jni.h>
+
+#include "android_webview/native/public/aw_assets.h"
+
+#include "base/android/jni_array.h"
+#include "base/android/jni_string.h"
+#include "base/android/scoped_java_ref.h"
+#include "jni/AwAssets_jni.h"
+
+namespace android_webview {
+namespace AwAssets {
+
+bool OpenAsset(const std::string& filename,
+               int* fd,
+               int64* offset,
+               int64* size) {
+  JNIEnv* env = base::android::AttachCurrentThread();
+  ScopedJavaLocalRef<jlongArray> jarr = Java_AwAssets_openAsset(
+      env,
+      base::android::GetApplicationContext(),
+      base::android::ConvertUTF8ToJavaString(env, filename).Release());
+  std::vector<jlong> results;
+  base::android::JavaLongArrayToLongVector(env, jarr.obj(), &results);
+  DCHECK_EQ(3U, results.size());
+  *fd = static_cast<int>(results[0]);
+  *offset = results[1];
+  *size = results[2];
+  return *fd != -1;
+}
+
+bool RegisterAssetWithGlobalDescriptors(base::GlobalDescriptors::Key key,
+                                        const std::string& asset_filename) {
+  int asset_fd = 0;
+  int64 asset_off = 0;
+  int64 asset_len = 0;
+  bool result =
+      AwAssets::OpenAsset(asset_filename, &asset_fd, &asset_off, &asset_len);
+  if (result) {
+    base::GlobalDescriptors::GetInstance()->Set(
+        key, asset_fd, base::MemoryMappedFile::Region(asset_off, asset_len));
+  }
+  return result;
+}
+
+}  // namespace AwAssets
+
+bool RegisterAwAssets(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+}  // namespace android_webview