Revert "Enable WebUI tab strip by default on ChromeOS"

This reverts commit 0a87896c48e5c14c6863a472d143432921ea7460.

Reason for revert: Speculative revert: suspecting this CL in TopControlsSlideControllerTest* test failures (see https://ci.chromium.org/p/chromium/builders/ci/linux-chromeos-rel)

Suspected regression log: https://chromium.googlesource.com/chromium/src/+log/8b22a3c1e6790d1316437664b2cac46f669860b2..3b2edb4c51e0db08a3a59c76e1f60a841ca7220d


Original change's description:
> Enable WebUI tab strip by default on ChromeOS
> 
> Bug: 1009881
> Change-Id: Ic3c00b61b8d9984b77b0d8e38a5a10d8a9c6e4d0
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1956241
> Reviewed-by: Peter Boström <[email protected]>
> Reviewed-by: Xiyuan Xia <[email protected]>
> Commit-Queue: Collin Baker <[email protected]>
> Cr-Commit-Position: refs/heads/master@{#724009}

[email protected],[email protected],[email protected]

Change-Id: I1466dd1790661df1c1cd3007250f2c9b11b98769
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1009881
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1963799
Reviewed-by: Roman Sorokin [CET] <[email protected]>
Commit-Queue: Roman Sorokin [CET] <[email protected]>
Cr-Commit-Position: refs/heads/master@{#724177}
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 77c0df2..55369f7 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -1733,7 +1733,7 @@
 #if BUILDFLAG(ENABLE_WEBUI_TAB_STRIP)
     {"webui-tab-strip", flag_descriptions::kWebUITabStripName,
      flag_descriptions::kWebUITabStripDescription, kOsDesktop,
-     FEATURE_VALUE_TYPE(features::kWebUITabStrip)},
+     SINGLE_VALUE_TYPE(switches::kWebUITabStrip)},
     {"webui-tab-strip-demo-options",
      flag_descriptions::kWebUITabStripDemoOptionsName,
      flag_descriptions::kWebUITabStripDemoOptionsDescription, kOsDesktop,