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

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 4fa9ea5fca5913f4a386315be3315ab1e5f792c9..cbcc851d7e6cc0d1be343b4db7d1ccde4f78cab2 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -2216,8 +2216,11 @@ const FeatureEntry kFeatureEntries[] = {
     {"enable-touchscreen-calibration", IDS_FLAGS_TOUCHSCREEN_CALIBRATION_NAME,
      IDS_FLAGS_TOUCHSCREEN_CALIBRATION_DESCRIPTION, kOsCrOS,
      SINGLE_VALUE_TYPE(chromeos::switches::kEnableTouchCalibrationSetting)},
-#endif // defined(OS_CHROMEOS)
 
+    {"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.