Introduce new flag to control usage of MD in secondary (not top-chrome)

chrome/browser/ui/views/download/download_item_view_md.cc

 // Copyright (c) 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.
 
 #include "chrome/browser/ui/views/download/download_item_view_md.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <vector>
@@ skipping 926 matching lines @@
   // to the user, so we start a new SamplingEvent and track it.
   std::string event_name = model_.MightBeMalicious()
                                ? ExperienceSamplingEvent::kMaliciousDownload
                                : ExperienceSamplingEvent::kDangerousDownload;
   sampling_event_.reset(new ExperienceSamplingEvent(
       event_name, download()->GetURL(), download()->GetReferrerUrl(),
       download()->GetBrowserContext()));
 
   dropdown_state_ = NORMAL;
   if (mode_ == DANGEROUS_MODE) {
-    save_button_ = views::MdTextButton::CreateStandardButton(
+    save_button_ = views::MdTextButton::CreateMdButton(
         this, model_.GetWarningConfirmButtonText());
     save_button_->SetStyle(views::Button::STYLE_BUTTON);
     AddChildView(save_button_);
   }
   int discard_button_message =
       model_.IsMalicious() ? IDS_DISMISS_DOWNLOAD : IDS_DISCARD_DOWNLOAD;
-  discard_button_ = views::MdTextButton::CreateStandardButton(
+  discard_button_ = views::MdTextButton::CreateMdButton(
       this, l10n_util::GetStringUTF16(discard_button_message));
   discard_button_->SetStyle(views::Button::STYLE_BUTTON);
   AddChildView(discard_button_);
 
   base::string16 dangerous_label =
       model_.GetWarningText(font_list_, kTextWidth);
   dangerous_download_label_ = new views::Label(dangerous_label);
   dangerous_download_label_->SetMultiLine(true);
   dangerous_download_label_->SetHorizontalAlignment(gfx::ALIGN_LEFT);
   dangerous_download_label_->SetAutoColorReadabilityEnabled(false);
@@ skipping 148 matching lines @@
     SchedulePaint();
 }
 
 SkColor DownloadItemViewMd::GetTextColor() const {
   return GetTextColorForThemeProvider(GetThemeProvider());
 }
 
 SkColor DownloadItemViewMd::GetDimmedTextColor() const {
   return SkColorSetA(GetTextColor(), 0xC7);
 }