Upstream most of the iOS WebUI support in ios/web/

ios/web/public/url_data_source_ios.h

Index: ios/web/public/url_data_source_ios.h
diff --git a/ios/web/public/url_data_source_ios.h b/ios/web/public/url_data_source_ios.h
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+// 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.
+
+#ifndef IOS_WEB_PUBLIC_URL_DATA_SOURCE_IOS_H_
+#define IOS_WEB_PUBLIC_URL_DATA_SOURCE_IOS_H_
+
+#include <string>
+
+#include "base/callback.h"
+
+namespace base {
+class MessageLoop;
+class RefCountedMemory;
+}
+
+namespace net {
+class URLRequest;
+}
+
+namespace web {
+class BrowserState;
+
+// A URLDataSourceIOS is an object that can answer requests for WebUI data
+// asynchronously. An implementation of URLDataSourceIOS should handle calls to
+// StartDataRequest() by starting its (implementation-specific) asynchronous
+// request for the data, then running the callback given in that method to
+// notify.
+class URLDataSourceIOS {
+ public:
+  // Adds a URL data source to |browser_state|.
+  static void Add(BrowserState* browser_state, URLDataSourceIOS* source);
+
+  virtual ~URLDataSourceIOS() {}
+
+  // The name of this source.
+  // E.g., for favicons, this could be "favicon", which results in paths for
+  // specific resources like "favicon/34" getting sent to this source. For
+  // sources where a scheme is used instead of the hostname as the unique
+  // identifier, the suffix "://" must be added to the return value, eg. for a
+  // URLDataSourceIOS which would display resources with URLs on the form
+  // your-scheme://anything , GetSource() must return "your-scheme://".
+  virtual std::string GetSource() const = 0;
+
+  // Used by StartDataRequest so that the child class can return the data when
+  // it's available.
+  typedef base::Callback<void(base::RefCountedMemory*)> GotDataCallback;
+
+  // Called by URLDataSourceIOS to request data at |path|. The string parameter
+  // is the path of the request. The child class should run |callback| when the
+  // data is available or if the request could not be satisfied. This can be
+  // called either in this callback or asynchronously with the response.
+  virtual void StartDataRequest(const std::string& path,
+                                const GotDataCallback& callback) = 0;
+
+  // Return the mimetype that should be sent with this response, or empty
+  // string to specify no mime type.
+  virtual std::string GetMimeType(const std::string& path) const = 0;
+
+  // The following methods are all called on the IO thread.
+
+  // Returns true if the URLDataSourceIOS should replace an existing
+  // URLDataSourceIOS with the same name that has already been registered. The
+  // default is true.
+  //
+  // WARNING: this is invoked on the IO thread.
+  //
+  // TODO: nuke this and convert all callers to not replace.
+  virtual bool ShouldReplaceExistingSource() const;
+
+  // Returns true if responses from this URLDataSourceIOS can be cached.
+  virtual bool AllowCaching() const;
+
+  // By default, "object-src 'none';" is added to CSP. Override to change this.
+  virtual std::string GetContentSecurityPolicyObjectSrc() const;
+
+  // By default, the "X-Frame-Options: DENY" header is sent. To stop this from
+  // happening, return false. It is OK to return false as needed.
+  virtual bool ShouldDenyXFrameOptions() const;
+
+  // By default, only chrome: requests are allowed.  Override in specific WebUI
+  // data sources to enable for additional schemes or to implement fancier
+  // access control.  Typically used in concert with
+  // WebClient::GetAdditionalWebUISchemes() to permit additional WebUI scheme
+  // support for an embedder.
+  virtual bool ShouldServiceRequest(const net::URLRequest* request) const;
+
+  // Called to inform the source that StartDataRequest() will be called soon.
+  // Gives the source an opportunity to rewrite |path| to incorporate extra
+  // information from the URLRequest prior to serving.
+  virtual void WillServiceRequest(const net::URLRequest* request,
+                                  std::string* path) const {}
+};
+
+}  // namespace web
+
+#endif  // IOS_WEB_PUBLIC_URL_DATA_SOURCE_IOS_H_