Displaying "simplify page" on print preview by default

chrome/browser/ui/tab_helpers.cc

 // 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.
 
 #include "chrome/browser/ui/tab_helpers.h"
 
 #include "base/command_line.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/content_settings/chrome_content_settings_client.h"
 #include "chrome/browser/content_settings/tab_specific_content_settings.h"
@@ skipping 218 matching lines @@
 #if defined(ENABLE_PRINTING) && !defined(OS_ANDROID)
 #if defined(ENABLE_PRINT_PREVIEW)
   printing::PrintViewManager::CreateForWebContents(web_contents);
   printing::PrintPreviewMessageHandler::CreateForWebContents(web_contents);
 #else
   printing::PrintViewManagerBasic::CreateForWebContents(web_contents);
 #endif  // defined(ENABLE_PRINT_PREVIEW)
 #endif  // defined(ENABLE_PRINTING) && !defined(OS_ANDROID)
 
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kEnableDomDistiller)) {
+          switches::kEnableDomDistiller) ||
+      !base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisablePrintPreviewSimplify)) {
     dom_distiller::WebContentsMainFrameObserver::CreateForWebContents(
         web_contents);
   }
 
   if (predictors::ResourcePrefetchPredictorFactory::GetForProfile(
       web_contents->GetBrowserContext())) {
     predictors::ResourcePrefetchPredictorTabHelper::CreateForWebContents(
         web_contents);
   }
 
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kEnableNavigationTracing) &&
       base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kTraceUploadURL)) {
     tracing::NavigationTracingObserver::CreateForWebContents(web_contents);
   }
 }