Add a flag to specify whether to show ARC Files app in launcher.

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 2198 matching lines @@
 #if defined(OS_ANDROID)
     {"lsd-permission-prompt", IDS_FLAGS_LSD_PERMISSION_PROMPT_NAME,
      IDS_FLAGS_LSD_PERMISSION_PROMPT_DESCRIPTION, kOsAndroid,
      FEATURE_VALUE_TYPE(features::kLsdPermissionPrompt)},
 #endif
 
 #if defined(OS_CHROMEOS)
     {"enable-touchscreen-calibration", IDS_FLAGS_TOUCHSCREEN_CALIBRATION_NAME,
      IDS_FLAGS_TOUCHSCREEN_CALIBRATION_DESCRIPTION, kOsCrOS,
      SINGLE_VALUE_TYPE(chromeos::switches::kEnableTouchCalibrationSetting)},
+
+    {"show-arc-files-app", IDS_FLAGS_SHOW_ARC_FILES_APP_NAME,

[hirono, 2017/01/26 01:17:50]

Do we need to publish the flag for non-developers?
If no, I think just adding the launch flag without exposing it in the flags page
is enough for now because the flag does not change anything now.

[Steve McKay, 2017/01/26 19:36:26]

I think we want to let users turn this on on stable releases. We don't expect
many to do it, but it's part of the path to being enabled by default.


Still, we should verify w/ Weifang.

+      IDS_FLAGS_SHOW_ARC_FILES_APP_DESCRIPTION, kOsCrOS,
+      SINGLE_VALUE_TYPE(chromeos::switches::kShowArcFilesApp)},

[Alexei Svitkine (slow), 2017/01/27 17:33:45]

For new enable/disable style flags, the best practice is to use a base::Feature
- which you can use FEATURE_VALUE_TYPE() here for. Can you switch to that?

 #endif // defined(OS_CHROMEOS)
-
     // 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.
 };
 
 class FlagsStateSingleton {
  public:
   FlagsStateSingleton()
       : flags_state_(kFeatureEntries, arraysize(kFeatureEntries)) {}
   ~FlagsStateSingleton() {}
@@ skipping 188 matching lines @@
 const base::HistogramBase::Sample kBadSwitchFormatHistogramId = 0;
 
 const FeatureEntry* GetFeatureEntries(size_t* count) {
   *count = arraysize(kFeatureEntries);
   return kFeatureEntries;
 }
 
 }  // namespace testing
 
 }  // namespace about_flags