Move V8 snapshot loading code from isolate_holder to gin/v8_startup_data.{h,cc}.

gin/v8_initializer.h

+// 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.
+
+#ifndef GIN_V8_INITIALIZER_H_
+#define GIN_V8_INITIALIZER_H_
+
+#include "base/files/file.h"
+#include "gin/array_buffer.h"
+#include "gin/gin_export.h"
+#include "gin/public/isolate_holder.h"
+#include "gin/public/v8_platform.h"
+#include "v8/include/v8.h"
+
+namespace gin {
+
+class GIN_EXPORT V8Initializer {
+ public:
+  static const int kV8SnapshotBasePathKey;
+  static const char kNativesFileName[];
+  static const char kSnapshotFileName[];
+
+  // This should be called by IsolateHolder::Initialize().
+  static void Initialize(gin::IsolateHolder::ScriptMode mode,
+                         v8::ArrayBuffer::Allocator* allocator);

[rmcilroy, 2015/03/30 17:44:18]

It would be good if we could avoid exposing this method as part of the public
API, but I can't think of a good way of doing this without having IsolateHolder
friend V8Initializer, which I'm not particularly keen to do. Any thoughts
anyone?

+
+  // Get address and size information for currently loaded snapshot.
+  // If no snapshot is loaded, the return values are null for addresses
+  // and 0 for sizes.
+  static void GetV8ExternalSnapshotData(const char** natives_data_out,
+                                        int* natives_size_out,
+                                        const char** snapshot_data_out,
+                                        int* snapshot_size_out);
+
+#if defined(V8_USE_EXTERNAL_STARTUP_DATA)
+
+  // Load V8 snapshot from user provided platform file descriptors.
+  // The offset and size arguments, if non-zero, specify the portions
+  // of the files to be loaded. This methods returns true on success
+  // (or if snapshot is already loaded), false otherwise.
+  static bool LoadV8SnapshotFromFD(base::PlatformFile natives_fd,
+                                   int64 natives_offset,
+                                   int64 natives_size,
+                                   base::PlatformFile snapshot_fd,
+                                   int64 snapshot_offset,
+                                   int64 snapshot_size);
+
+  // Load V8 snapshot from default resources. Returns true on success or
+  // snapshot is already loaded, false otherwise.
+  static bool LoadV8Snapshot();
+
+#endif  // V8_USE_EXTERNAL_STARTUP_DATA
+};
+
+}  // namespace gin
+
+#endif  // GIN_V8_INITIALIZER_H_