[iOS] Delete expired Safe Browsing flags

This removes safe-browsing-real-time from about:flags since the
feature is enabled by default and has shipped to 100% of Stable.

This also removes safe-browsing-available from flag-metadata.json.
This flag was removed from about:flags in a previous CL, but the
flag-metadata.json entry was left behind.

Bug: 1028755
Change-Id: I62b90e18594f906d3bc7e87392fe2afcd35f8f72
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2595609
Auto-Submit: Ali Juma <ajuma@chromium.org>
Commit-Queue: Eugene But <eugenebut@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#837715}

chrome/browser/flag-metadata.json

@@ -4230,11 +4230,6 @@
     "owners": [ "armax", "guidou" ],
     "expiry_milestone": 90
   },
-  {
-    "name": "safe-browsing-available",
-    "owners": [ "//ios/chrome/browser/safe_browsing/OWNERS", "bling-flags@google.com" ],
-    "expiry_milestone": 87
-  },
   {
     "name": "safe-browsing-client-side-detection-android",
     "owners": [
@@ -4266,11 +4261,6 @@
     "owners": [ "bdea", "chrome-safebrowsing-core@google.com" ],
     "expiry_milestone": 90
   },
-  {
-    "name": "safe-browsing-real-time",
-    "owners": [ "//ios/chrome/browser/safe_browsing/OWNERS", "bling-flags@google.com" ],
-    "expiry_milestone": 88
-  },
   {
     "name": "safe-browsing-security-section-ui-android",
     "owners": [

ios/chrome/browser/flags/about_flags.mm

@@ -43,7 +43,6 @@
 #include "components/payments/core/features.h"
 #import "components/policy/core/common/policy_loader_ios_constants.h"
 #include "components/policy/policy_constants.h"
-#include "components/safe_browsing/core/features.h"
 #include "components/security_state/core/features.h"
 #include "components/send_tab_to_self/features.h"
 #include "components/signin/core/browser/account_reconcilor.h"
@@ -435,11 +434,6 @@ const flags_ui::FeatureEntry kFeatureEntries[] = {
      flags_ui::kOsIos,
      FEATURE_VALUE_TYPE(
          fullscreen::features::kFullscreenControllerBrowserScoped)},
-    {"safe-browsing-real-time",
-     flag_descriptions::kSafeBrowsingRealTimeLookupName,
-     flag_descriptions::kSafeBrowsingRealTimeLookupDescription,
-     flags_ui::kOsIos,
-     FEATURE_VALUE_TYPE(safe_browsing::kRealTimeUrlLookupEnabled)},
     {"managed-bookmarks-ios", flag_descriptions::kManagedBookmarksIOSName,
      flag_descriptions::kManagedBookmarksIOSDescription, flags_ui::kOsIos,
      FEATURE_VALUE_TYPE(kManagedBookmarksIOS)},