Upstream Chrome on iOS source code [6/11].

ios/chrome/browser/ui/omnibox/preload_provider.h

+// Copyright 2012 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_CHROME_BROWSER_UI_OMNIBOX_PRELOAD_PROVIDER_H_
+#define IOS_CHROME_BROWSER_UI_OMNIBOX_PRELOAD_PROVIDER_H_
+
+#import <UIKit/UIKit.h>
+
+#include "ui/base/page_transition_types.h"
+#include "url/gurl.h"
+
+namespace web {
+struct Referrer;
+}
+
+// Protocol for an object that provides preloading capabilities.
+@protocol PreloadProvider
+
+// Prerenders the given |url| with the given |transition|.  Normally, prerender
+// requests are fulfilled after a short delay, to prevent unnecessary prerenders
+// while the user is typing.  If |immediately| is YES, this method starts
+// prerendering immediately, with no delay.  |immediately| should be set to YES
+// only when there is a very high confidence that the user will navigate to the
+// given |url|.
+//
+// If there is already an existing request for |url|, this method does nothing
+// and does not reset the delay timer.  If there is an existing request for a
+// different URL, this method cancels that request and queues this request
+// instead.
+- (void)prerenderURL:(const GURL&)url
+            referrer:(const web::Referrer&)referrer
+          transition:(ui::PageTransition)transition
+         immediately:(BOOL)immediately;
+
+// Cancels any outstanding prerender requests and destroys any prerendered Tabs.
+- (void)cancelPrerender;
+
+// Prefetches the |url|.
+- (void)prefetchURL:(const GURL&)url transition:(ui::PageTransition)transition;
+
+// Cancels any outstanding prefetch requests.
+- (void)cancelPrefetch;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_OMNIBOX_PRELOAD_PROVIDER_H_