Adds persistent downloads's flag

- Adds persistent downloads's flag.

Bug: 1013072
Change-Id: Ic5db8f631d0740748807434fddb52ba1da5505f0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1852086
Commit-Queue: Ewann Pellé <ewannpv@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#712966}

ios/chrome/browser/flags/about_flags.mm

@@ -562,6 +562,10 @@ const flags_ui::FeatureEntry kFeatureEntries[] = {
      flags_ui::kOsIos,
      FEATURE_VALUE_TYPE(
          autofill::features::kAutofillSaveCardDismissOnNavigation)},
+    {"enable-persistent-downloads",
+     flag_descriptions::kEnablePersistentDownloadsName,
+     flag_descriptions::kEnablePersistentDownloadsDescription, flags_ui::kOsIos,
+     FEATURE_VALUE_TYPE(web::features::kEnablePersistentDownloads)},
 };
 
 // Add all switches from experimental flags to |command_line|.

ios/chrome/browser/flags/ios_chrome_flag_descriptions.cc

@@ -185,6 +185,10 @@ const char kEnableClipboardProviderTextSuggestionsName[] =
 const char kEnableClipboardProviderTextSuggestionsDescription[] =
     "Enable suggesting a search for text copied to the clipboard";
 
+const char kEnablePersistentDownloadsName[] = "Enable persistent downloads";
+const char kEnablePersistentDownloadsDescription[] =
+    "Enables the new, experimental implementation of persistent downloads";
+
 const char kEnableSyncUSSPasswordsName[] = "Enable USS for passwords sync";
 const char kEnableSyncUSSPasswordsDescription[] =
     "Enables the new, experimental implementation of password sync";

ios/chrome/browser/flags/ios_chrome_flag_descriptions.h

@@ -153,6 +153,10 @@ extern const char kEnableClipboardProviderImageSuggestionsDescription[];
 extern const char kEnableClipboardProviderTextSuggestionsName[];
 extern const char kEnableClipboardProviderTextSuggestionsDescription[];
 
+// Title and description for the flag to enable persistent downloads.
+extern const char kEnablePersistentDownloadsName[];
+extern const char kEnablePersistentDownloadsDescription[];
+
 extern const char kEnableSyncUSSPasswordsName[];
 extern const char kEnableSyncUSSPasswordsDescription[];
 

ios/web/common/features.h

@@ -45,6 +45,9 @@ extern const base::Feature kUseWKWebViewLoading;
 // Feature flag to move -LogLoadStarted() to WebStateDidStartNavigation().
 extern const base::Feature kLogLoadStartedInDidStartNavigation;
 
+// Feature flag enabling persistent downloads.
+extern const base::Feature kEnablePersistentDownloads;
+
 // Use WKWebView.loading to update WebState::IsLoading.
 // TODO(crbug.com/1006012): Clean up this flag after experiment.
 bool UseWKWebViewLoading();

ios/web/common/features.mm

@@ -41,6 +41,9 @@ const base::Feature kUseWKWebViewLoading{"UseWKWebViewLoading",
 const base::Feature kLogLoadStartedInDidStartNavigation{
     "LogLoadStartedInDidStartNavigation", base::FEATURE_ENABLED_BY_DEFAULT};
 
+const base::Feature kEnablePersistentDownloads{
+    "EnablePersistentDownloads", base::FEATURE_DISABLED_BY_DEFAULT};
+
 // The feature kUseWKWebViewLoading will change the CPM if
 // kLogLoadStartedInDidStartNavigation is not enabled, so
 // kLogLoadStartedInDidStartNavigation is required. The feature flag