Disable Quick View by default and add about flag to enable it.

chrome/browser/about_flags.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/about_flags.h"
 
 #include <iterator>
 #include <map>
 #include <set>
 #include <utility>
@@ skipping 1951 matching lines @@
      FEATURE_VALUE_TYPE(password_manager::features::kFillOnAccountSelect)},
     {"new-audio-rendering-mixing-strategy",  // FLAGS:RECORD_UMA
      IDS_NEW_AUDIO_RENDERING_MIXING_STRATEGY_NAME,
      IDS_NEW_AUDIO_RENDERING_MIXING_STRATEGY_DESCRIPTION,
      kOsWin | kOsMac | kOsLinux | kOsAndroid,
      FEATURE_VALUE_TYPE(media::kNewAudioRenderingMixingStrategy)},
 #if defined(OS_CHROMEOS)
     {"enable-intent-picker", IDS_ENABLE_INTENT_PICKER,
      IDS_ENABLE_INTENT_PICKER_DESCRIPTION, kOsCrOS,
      SINGLE_VALUE_TYPE(switches::kEnableIntentPicker)},
+    {"files-quick-view", IDS_FLAGS_FILES_QUICK_VIEW_NAME,
+     IDS_FLAGS_FILES_QUICK_VIEW_DESCRIPTION, kOsCrOS,
+     ENABLE_DISABLE_VALUE_TYPE(chromeos::switches::kEnableFilesQuickView,
+                               chromeos::switches::kDisableFilesQuickView)},
 #endif  // defined(OS_CHROMEOS)
 #if defined(OS_ANDROID)
     {"enable-web-payments", IDS_FLAGS_ENABLE_WEB_PAYMENTS_NAME,
      IDS_FLAGS_ENABLE_WEB_PAYMENTS_DESCRIPTION, kOsAndroid,
      FEATURE_VALUE_TYPE(features::kWebPayments)},
 #endif  // defined(OS_ANDROID)
     // NOTE: Adding new command-line switches requires adding corresponding
     // entries to enum "LoginCustomFlags" in histograms.xml. See note in
     // histograms.xml and don't forget to run AboutFlagsHistogramTest unit test.
 };
@@ skipping 183 matching lines @@
 const base::HistogramBase::Sample kBadSwitchFormatHistogramId = 0;
 
 const FeatureEntry* GetFeatureEntries(size_t* count) {
   *count = arraysize(kFeatureEntries);
   return kFeatureEntries;
 }
 
 }  // namespace testing
 
 }  // namespace about_flags