Added support for heavy page previews transformations

components/data_reduction_proxy/core/common/lofi_decider.h

 // Copyright 2015 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 COMPONENTS_DATA_REDUCTION_PROXY_CORE_BROWSER_LOFI_DECIDER_H_
 #define COMPONENTS_DATA_REDUCTION_PROXY_CORE_BROWSER_LOFI_DECIDER_H_
 
 #include "base/macros.h"
 
 namespace net {
@@ skipping 13 matching lines @@
   // Lo-Fi header should be added to the given request.
   virtual bool IsUsingLoFiMode(const net::URLRequest& request) const = 0;
 
   // Adds a previews-specific directive to the Chrome-Proxy-Accept-Transform
   // header if needed. If a slow page preview is triggered, adds "lite-page" or
   // "empty-image", depending on whether the request is for the main frame
   // and lite pages are enabled, or for a subresource and Lo-Fi mode is enabled,
   // respectively. If a slow page preview is not triggered, "lite-page;if-heavy"
   // and "empty-image;if-heavy" are added in the respective aforementioned cases
   // to request that the server transform the page if it determines it to be
-  // heavy.
+  // heavy. Previews-related transformation headers are never added if
+  // |is_previews_disabled| is true.
   virtual void MaybeSetAcceptTransformHeader(
       const net::URLRequest& request,
+      bool is_previews_disabled,
       net::HttpRequestHeaders* headers) const = 0;
 
   // Returns true if |headers| contains the Chrome-Proxy-Accept-Transform
   // header and a slow page previews directive ("lite-page" or "empty-image")
   // is present and not conditioned on "if-heavy".
   virtual bool IsSlowPagePreviewRequested(
       const net::HttpRequestHeaders& headers) const = 0;
 
   // Returns true if |headers| contains the Chrome-Proxy-Accept-Transform
   // header with the "lite-page" directive.
@@ skipping 12 matching lines @@
 
   // Returns true if the Lo-Fi specific UMA should be recorded. It is set to
   // true if Lo-Fi is enabled for |request|, Chrome session is in Lo-Fi
   // Enabled or Control field trial, and the network quality was slow.
   virtual bool ShouldRecordLoFiUMA(const net::URLRequest& request) const = 0;
 };
 
 }  // namespace data_reduction_proxy
 
 #endif  // COMPONENTS_DATA_REDUCTION_PROXY_CORE_BROWSER_LOFI_DECIDER_H_