Disable Metered toggle by default

The logic for determining whether a network is metered for the purpose
of auto updates is implemented separately in session_manager. We need
to resolve this before enabling the toggle. See issue for details.

Bug: 1129994
Change-Id: I976e191b8b27017339876d747c01967bab6081dc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2426982
Auto-Submit: Steven Bennetts <stevenjb@chromium.org>
Reviewed-by: James Vecore <vecore@google.com>
Commit-Queue: Steven Bennetts <stevenjb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810244}

chrome/common/chrome_features.cc

@@ -517,7 +517,7 @@ const base::Feature kMacSystemScreenCapturePermissionCheck{
 // Whether to show the Metered toggle in Settings, allowing users to toggle
 // whether to treat a WiFi or Cellular network as 'metered'.
 const base::Feature kMeteredShowToggle{"MeteredShowToggle",
-                                       base::FEATURE_ENABLED_BY_DEFAULT};
+                                       base::FEATURE_DISABLED_BY_DEFAULT};
 #endif
 
 // Enables showing an entry for mixed content in site settings, which controls