Add flags and experiment config for selecting triggering heuristics

components/dom_distiller/content/distillable_page_utils.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_DOM_DISTILLER_CONTENT_DISTILLABLE_PAGE_UTILS_H_
 #define COMPONENTS_DOM_DISTILLER_CONTENT_DISTILLABLE_PAGE_UTILS_H_
 
 #include "base/callback.h"
 #include "content/public/browser/web_contents.h"
 
 namespace dom_distiller {
 
 class DistillablePageDetector;
 
+// Checks if the page appears to be distillable based on whichever heuristics
+// are configured to be used (see dom_distiller::GetDistillerHeuristicsType).
+void IsDistillablePage(content::WebContents* web_contents,
+                       base::Callback<void(bool)> callback);
+
+// Checks if the web_contents is has opengraph type=article markup.
 void IsOpenGraphArticle(content::WebContents* web_contents,
                         base::Callback<void(bool)> callback);
-void IsDistillablePage(content::WebContents* web_contents,
-                       base::Callback<void(bool)> callback);
-// The passed detector must be alive until after the callback is called.
+
+// Uses the provided DistillablePageDetector to detect if the page is
+// distillable. The passed detector must be alive until after the callback is
+// called.
 void IsDistillablePageForDetector(content::WebContents* web_contents,
                                   const DistillablePageDetector* detector,
                                   base::Callback<void(bool)> callback);
 }
 
 #endif  // COMPONENTS_DOM_DISTILLER_CONTENT_DISTILLABLE_PAGE_UTILS_H_