Deduplicating CanReadRequestBody code.

content/browser/resource_request_body_browser_utils.h

+// Copyright 2017 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 CONTENT_BROWSER_RESOURCE_REQUEST_BODY_BROWSER_UTILS_H_
+#define CONTENT_BROWSER_RESOURCE_REQUEST_BODY_BROWSER_UTILS_H_

[Łukasz Anforowicz, 2017/05/25 16:11:37]

I don't see another good place for the new helper functions.

The functions depend on storage::FileSystemContext, so maybe they should go into
content/browser/fileapi/browser_file_system_helper.h (similarily to
PrepareDropDataForChildProcess), but the ResourceRequestBodyImpl encompasses
more than just the filesystem stuff, browser_file_system_helper.h doesn't seem
right.

I think the new function(s) would be a great instance method of
ResourceRequestBodyImpl, but the problem is that the new function should only be
used from the browser (not from the renderer) and I don't see how to enforce
this when by necessity ResourceRequestBodyImpl is declared in
content/*common*/resource_request_body_impl.h.

+
+#include "base/memory/ref_counted.h"
+
+namespace storage {
+class FileSystemContext;
+}  // namespace storage
+
+namespace content {
+
+class SiteInstance;
+class ResourceRequestBodyImpl;
+
+// Checks if |child_id| and |file_system_context| can read all elements of
+// |body|.
+bool CanReadRequestBody(int child_id,
+                        const storage::FileSystemContext* file_system_context,
+                        const scoped_refptr<ResourceRequestBodyImpl>& body);

[Łukasz Anforowicz, 2017/05/25 16:11:37]

This overload is used from ResourceDispatcherHostImpl::ShouldServiceRequest.

[mmenke, 2017/05/25 17:20:25]

Overloads are generally discouraged.  Also it might be nice if there were some
way to figure out at callsites that this is coming from another file (static
method in a class that's never instantiated?  Prefix?)

+
+// Checks if |site_instance| can read all elements of |body|.
+bool CanReadRequestBody(SiteInstance* site_instance,
+                        const scoped_refptr<ResourceRequestBodyImpl>& body);

[Łukasz Anforowicz, 2017/05/25 16:11:37]

This overload is used from RenderFrameHostImpl::OnBeginNavigation and
RenderFrameProxyHost::OnOpenURL.

+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RESOURCE_REQUEST_BODY_BROWSER_UTILS_H_