Add UMA histogram DomDistiller.Time.DistillPage

components/dom_distiller/core/distiller_page.h

 // Copyright 2013 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_CORE_DISTILLER_PAGE_H_
 #define COMPONENTS_DOM_DISTILLER_CORE_DISTILLER_PAGE_H_
 
 #include <string>
 
 #include "base/callback.h"
@@ skipping 48 matching lines @@
   // either a dictionary with all the content, or a stringified version.
   virtual bool StringifyOutput() = 0;
 
   // If true, forces the creation of a new window context to evaluate the
   // JavaScript.
   virtual bool CreateNewContext() = 0;
 
  private:
   bool ready_;
   DistillerPageCallback distiller_page_callback_;
+  base::TimeTicks distillation_start_;
   DISALLOW_COPY_AND_ASSIGN(DistillerPage);
 };
 
 // Factory for generating a |DistillerPage|.
 class DistillerPageFactory {
  public:
   virtual ~DistillerPageFactory();
 
   // Constructs and returns a new DistillerPage. The implementation of this
   // should be very cheap, since the pages can be thrown away without being
   // used.
   virtual scoped_ptr<DistillerPage> CreateDistillerPage(
       const gfx::Size& render_view_size) const = 0;
   virtual scoped_ptr<DistillerPage> CreateDistillerPageWithHandle(
       scoped_ptr<SourcePageHandle> handle) const = 0;
 };
 
 }  // namespace dom_distiller
 
 #endif  // COMPONENTS_DOM_DISTILLER_CORE_DISTILLER_PAGE_H_