Revert "SearchProviderLogos: Add about:flags entry for UseDdljsonApi on iOS"

This reverts commit 2752e8be.

Reason for revert: 
This has since been removed from other platforms. 
The easiest and most transparent way to remove this flag is to revert this CL.

Original change's description:
> SearchProviderLogos: Add about:flags entry for UseDdljsonApi on iOS
> 
> This is basically the iOS version of
> https://chromium-review.googlesource.com/c/600309.
> It'll make manual testing of the feature much easier.
> 
> Bug: 690467
> Change-Id: I46656106f42821346bb323c655296e63e4ddd2b1
> Reviewed-on: https://chromium-review.googlesource.com/602129
> Reviewed-by: Rohit Rao (ping after 24h) <rohitrao@chromium.org>
> Commit-Queue: Marc Treib <treib@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#492020}

TBR=rohitrao@chromium.org,treib@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 690467
Change-Id: I48510ac9539f101bd6927c161473b71185af7af1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2095399Reviewed-by: edchin <edchin@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Commit-Queue: edchin <edchin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#748321}

ios/chrome/browser/BUILD.gn

@@ -80,7 +80,6 @@ source_set("browser") {
     "//components/proxy_config/ios",
     "//components/reading_list/ios",
     "//components/search_engines",
-    "//components/search_provider_logos",
     "//components/security_state/core",
     "//components/send_tab_to_self",
     "//components/strings",

ios/chrome/browser/flags/about_flags.mm

@@ -39,7 +39,6 @@
 #include "components/omnibox/common/omnibox_features.h"
 #include "components/password_manager/core/common/password_manager_features.h"
 #include "components/payments/core/features.h"
-#include "components/search_provider_logos/switches.h"
 #include "components/security_state/core/features.h"
 #include "components/send_tab_to_self/features.h"
 #include "components/signin/core/browser/account_reconcilor.h"
@@ -106,20 +105,6 @@ const FeatureEntry::FeatureVariation kMarkHttpAsFeatureVariations[] = {
     {"(mark with a grey triangle icon)", kMarkHttpAsDangerWarning,
      base::size(kMarkHttpAsDangerWarning), nullptr}};
 
-const FeatureEntry::Choice kUseDdljsonApiChoices[] = {
-    {flags_ui::kGenericExperimentChoiceDefault, "", ""},
-    {"(force test doodle 0)", search_provider_logos::switches::kGoogleDoodleUrl,
-     "https://www.gstatic.com/chrome/ntp/doodle_test/ddljson_ios0.json"},
-    {"(force test doodle 1)", search_provider_logos::switches::kGoogleDoodleUrl,
-     "https://www.gstatic.com/chrome/ntp/doodle_test/ddljson_ios1.json"},
-    {"(force test doodle 2)", search_provider_logos::switches::kGoogleDoodleUrl,
-     "https://www.gstatic.com/chrome/ntp/doodle_test/ddljson_ios2.json"},
-    {"(force test doodle 3)", search_provider_logos::switches::kGoogleDoodleUrl,
-     "https://www.gstatic.com/chrome/ntp/doodle_test/ddljson_ios3.json"},
-    {"(force test doodle 4)", search_provider_logos::switches::kGoogleDoodleUrl,
-     "https://www.gstatic.com/chrome/ntp/doodle_test/ddljson_ios4.json"},
-};
-
 const FeatureEntry::Choice kAutofillIOSDelayBetweenFieldsChoices[] = {
     {flags_ui::kGenericExperimentChoiceDefault, "", ""},
     {"0", autofill::switches::kAutofillIOSDelayBetweenFields, "0"},
@@ -286,9 +271,6 @@ const flags_ui::FeatureEntry kFeatureEntries[] = {
          feature_engagement::kIPHDemoMode,
          feature_engagement::kIPHDemoModeChoiceVariations,
          "IPH_DemoMode")},
-    {"use-ddljson-api", flag_descriptions::kUseDdljsonApiName,
-     flag_descriptions::kUseDdljsonApiDescription, flags_ui::kOsIos,
-     MULTI_VALUE_TYPE(kUseDdljsonApiChoices)},
     {"drag_and_drop", flag_descriptions::kDragAndDropName,
      flag_descriptions::kDragAndDropDescription, flags_ui::kOsIos,
      FEATURE_VALUE_TYPE(kDragAndDrop)},

ios/chrome/browser/flags/ios_chrome_flag_descriptions.cc

@@ -400,10 +400,6 @@ const char kTranslateInfobarMessagesUIName[] =
 const char kTranslateInfobarMessagesUIDescription[] =
     "When enabled, the Translate Infobar uses the new Messages UI.";
 
-const char kUseDdljsonApiName[] = "Use new ddljson API for Doodles";
-const char kUseDdljsonApiDescription[] =
-    "Enables the new ddljson API to fetch Doodles for the NTP.";
-
 const char kWalletServiceUseSandboxName[] = "Use Google Payments sandbox";
 const char kWalletServiceUseSandboxDescription[] =
     "Uses the sandbox service for Google Payments API calls.";

ios/chrome/browser/flags/ios_chrome_flag_descriptions.h

@@ -349,10 +349,6 @@ extern const char kToolbarNewTabButtonDescription[];
 extern const char kTranslateInfobarMessagesUIName[];
 extern const char kTranslateInfobarMessagesUIDescription[];
 
-// Title and description for the flag to enable the ddljson Doodle API.
-extern const char kUseDdljsonApiName[];
-extern const char kUseDdljsonApiDescription[];
-
 // Title and description for the flag to control if Google Payments API calls
 // should use the sandbox servers.
 extern const char kWalletServiceUseSandboxName[];