[CORS-RFC1918] Delete unused feature flag.

It was mistakenly added in crrev.com/c/2282932 after a bad rebase
operation.

Bug: chromium:986744
Change-Id: Iefdfac6cfa564f7d4cd3b12b7a322f56a2945ecc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2366734Reviewed-by: Christian Dullweber <dullweber@chromium.org>
Commit-Queue: Titouan Rigoudy <titouan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#800082}

components/content_settings/core/common/features.cc

@@ -23,7 +23,4 @@ const base::Feature kDisallowExtensionsToSetPluginContentSettings{
     "DisallowExtensionsToSetPluginContentSettings",
     base::FEATURE_ENABLED_BY_DEFAULT};
 
-const base::Feature kBlockInsecurePrivateNetworkRequests{
-    "BlockInsecurePrivateNetworkRequests", base::FEATURE_DISABLED_BY_DEFAULT};
-
 }  // namespace content_settings

components/content_settings/core/common/features.h

@@ -29,14 +29,6 @@ extern const base::Feature kDisallowWildcardsInPluginContentSettings;
 COMPONENT_EXPORT(CONTENT_SETTINGS_FEATURES)
 extern const base::Feature kDisallowExtensionsToSetPluginContentSettings;
 
-// When kBlockInsecurePrivateNetworkRequests is enabled, requests initiated
-// from a less-private network may only target a more-private network if the
-// initiating context is secure.
-//
-// See also: https://wicg.github.io/cors-rfc1918/#integration-fetch
-COMPONENT_EXPORT(CONTENT_SETTINGS_FEATURES)
-extern const base::Feature kBlockInsecurePrivateNetworkRequests;
-
 }  // namespace content_settings
 
 #endif  // COMPONENTS_CONTENT_SETTINGS_CORE_COMMON_FEATURES_H_