Adds kIdentityDisc experiment flag for iOS

No functional change, just added the feature flag kIdentityDisc
and the name/description for chrome://flags.

This matches the same feature flag added in http://crrev/c/1600391

Bug: 961120
Change-Id: Iac358e45a438f6b437ef52e7e72c276d747abfe5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1602052
Commit-Queue: Peter Lee <pkl@chromium.org>
Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Reviewed-by: Jérôme Lebel <jlebel@chromium.org>
Auto-Submit: Peter Lee <pkl@chromium.org>
Cr-Commit-Position: refs/heads/master@{#658641}

ios/chrome/browser/about_flags.mm

@@ -586,6 +586,9 @@ const flags_ui::FeatureEntry kFeatureEntries[] = {
     {"lock-bottom-toolbar", flag_descriptions::kLockBottomToolbarName,
      flag_descriptions::kLockBottomToolbarDescription, flags_ui::kOsIos,
      FEATURE_VALUE_TYPE(fullscreen::features::kLockBottomToolbar)},
+    {"identity-disc", flag_descriptions::kIdentityDiscName,
+     flag_descriptions::kIdentityDiscDescription, flags_ui::kOsIos,
+     FEATURE_VALUE_TYPE(kIdentityDisc)},
 };
 
 // Add all switches from experimental flags to |command_line|.

ios/chrome/browser/ios_chrome_flag_descriptions.cc

@@ -278,6 +278,10 @@ const char kHistoryBatchUpdatesFilterDescription[] =
     "When enabled History inserts and deletes history items in the same "
     "BatchUpdates block.";
 
+const char kIdentityDiscName[] = "Identity Disc";
+const char kIdentityDiscDescription[] =
+    "Enables Identity Disc, profile avatar icon button in toolbar.";
+
 const char kInfobarUIRebootName[] = "Infobar UI Reboot";
 const char kInfobarUIRebootDescription[] =
     "When enabled, Infobar will use the new UI.";

ios/chrome/browser/ios_chrome_flag_descriptions.h

@@ -227,6 +227,11 @@ extern const char kFullscreenViewportAdjustmentExperimentDescription[];
 extern const char kHistoryBatchUpdatesFilterName[];
 extern const char kHistoryBatchUpdatesFilterDescription[];
 
+// Title and description for the flag to display current user identity on
+// New Tab Page.
+extern const char kIdentityDiscName[];
+extern const char kIdentityDiscDescription[];
+
 // Title and description for the flag to enable the new UI Reboot on Infobars.
 extern const char kInfobarUIRebootName[];
 extern const char kInfobarUIRebootDescription[];

ios/chrome/browser/signin/feature_flags.h

@@ -10,4 +10,7 @@
 // Feature flag to enable NSURLSession for GAIAAuthFetcherIOS.
 extern const base::Feature kUseNSURLSessionForGaiaSigninRequests;
 
+// Feature flag to enable display of current user identity on New Tab Page.
+extern const base::Feature kIdentityDisc;
+
 #endif  // IOS_CHROME_BROWSER_SIGNIN_FEATURE_FLAGS_H_

ios/chrome/browser/signin/feature_flags.mm

@@ -13,3 +13,6 @@
 // See: http://crbug.com/939508.
 const base::Feature kUseNSURLSessionForGaiaSigninRequests{
     "UseNSURLSessionForGaiaSigninRequests", base::FEATURE_DISABLED_BY_DEFAULT};
+
+const base::Feature kIdentityDisc{"IdentityDisc",
+                                  base::FEATURE_DISABLED_BY_DEFAULT};