# Add flag to disable automatic search engine collection

--- a/chrome/browser/ungoogled_flag_entries.h
+++ b/chrome/browser/ungoogled_flag_entries.h
@@ -12,4 +12,8 @@
      "Handling of extension MIME type requests",
      "Used when deciding how to handle a request for a CRX or User Script MIME type.  ungoogled-chromium flag.",
      kOsAll, MULTI_VALUE_TYPE(kExtensionHandlingChoices)},
+    {"disable-search-engine-collection",
+     "Disable search engine collection",
+     "Prevents search engines from being added automatically.  ungoogled-chromium flag.",
+     kOsAll, SINGLE_VALUE_TYPE("disable-search-engine-collection")},
 #endif  // CHROME_BROWSER_UNGOOGLED_FLAG_ENTRIES_H_
--- a/chrome/renderer/chrome_render_frame_observer.cc
+++ b/chrome/renderer/chrome_render_frame_observer.cc
@@ -139,9 +139,10 @@ ChromeRenderFrameObserver::ChromeRenderF
   if (!render_frame->IsMainFrame())
     return;
 
-#if BUILDFLAG(SAFE_BROWSING_AVAILABLE)
   const base::CommandLine& command_line =
       *base::CommandLine::ForCurrentProcess();
+  should_autocollect_ = !command_line.HasSwitch("disable-search-engine-collection");
+#if BUILDFLAG(SAFE_BROWSING_AVAILABLE)
   if (!command_line.HasSwitch(switches::kDisableClientSidePhishingDetection))
     SetClientSidePhishingDetection();
 #endif
@@ -201,14 +202,16 @@ void ChromeRenderFrameObserver::DidFinis
   if (frame->Parent())
     return;
 
-  GURL osdd_url = frame->GetDocument().OpenSearchDescriptionURL();
-  if (!osdd_url.is_empty()) {
-    mojo::AssociatedRemote<chrome::mojom::OpenSearchDescriptionDocumentHandler>
-        osdd_handler;
-    render_frame()->GetRemoteAssociatedInterfaces()->GetInterface(
-        &osdd_handler);
-    osdd_handler->PageHasOpenSearchDescriptionDocument(
-        frame->GetDocument().Url(), osdd_url);
+  if (should_autocollect_) {
+    GURL osdd_url = frame->GetDocument().OpenSearchDescriptionURL();
+    if (!osdd_url.is_empty()) {
+      mojo::AssociatedRemote<chrome::mojom::OpenSearchDescriptionDocumentHandler>
+          osdd_handler;
+      render_frame()->GetRemoteAssociatedInterfaces()->GetInterface(
+          &osdd_handler);
+      osdd_handler->PageHasOpenSearchDescriptionDocument(
+          frame->GetDocument().Url(), osdd_url);
+    }
   }
 }
 
--- a/chrome/renderer/chrome_render_frame_observer.h
+++ b/chrome/renderer/chrome_render_frame_observer.h
@@ -139,6 +139,7 @@ class ChromeRenderFrameObserver : public
 #if BUILDFLAG(SAFE_BROWSING_AVAILABLE)
   safe_browsing::PhishingClassifierDelegate* phishing_classifier_ = nullptr;
 #endif
+  bool should_autocollect_; // Whether to autocollect search engines
 
   // Owned by ChromeContentRendererClient and outlive us.
   web_cache::WebCacheImpl* web_cache_impl_;
--- a/components/search_engines/template_url_service.cc
+++ b/components/search_engines/template_url_service.cc
@@ -12,6 +12,7 @@
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/callback_helpers.h"
+#include "base/command_line.h"
 #include "base/containers/contains.h"
 #include "base/debug/crash_logging.h"
 #include "base/format_macros.h"
@@ -197,6 +198,12 @@ bool IsCreatedByExtension(const Template
          template_url->type() == TemplateURL::OMNIBOX_API_EXTENSION;
 }
 
+bool ShouldAutocollect() {
+  const base::CommandLine& command_line =
+    *base::CommandLine::ForCurrentProcess();
+  return !command_line.HasSwitch("disable-search-engine-collection");
+}
+
 }  // namespace
 
 // TemplateURLService::LessWithPrefix -----------------------------------------
@@ -282,6 +289,7 @@ TemplateURLService::TemplateURLService(
     std::unique_ptr<TemplateURLServiceClient> client,
     const base::RepeatingClosure& dsp_change_callback)
     : prefs_(prefs),
+      should_autocollect_(true),
       search_terms_data_(std::move(search_terms_data)),
       web_data_service_(web_data_service),
       client_(std::move(client)),
@@ -363,8 +371,8 @@ bool TemplateURLService::CanAddAutogener
   // that may interfere with search queries).  An easy heuristic for this is
   // whether the user has a TemplateURL that has been manually modified (e.g.,
   // renamed) connected to the same host.
-  return !url.is_valid() || url.host().empty() ||
-      CanAddAutogeneratedKeywordForHost(url.host());
+  return should_autocollect_ && (!url.is_valid() || url.host().empty() ||
+      CanAddAutogeneratedKeywordForHost(url.host()));
 }
 
 bool TemplateURLService::IsPrepopulatedOrCreatedByPolicy(
@@ -1500,6 +1508,8 @@ SyncDataMap TemplateURLService::CreateGU
 
 void TemplateURLService::Init(const Initializer* initializers,
                               int num_initializers) {
+  should_autocollect_ = ShouldAutocollect();
+
   if (client_)
     client_->SetOwner(this);
 
@@ -1636,6 +1646,9 @@ void TemplateURLService::ChangeToLoadedS
 
 bool TemplateURLService::CanAddAutogeneratedKeywordForHost(
     const std::string& host) const {
+  if (!should_autocollect_)
+    return false;
+
   const TemplateURLSet* urls = provider_map_->GetURLsForHost(host);
   if (!urls)
     return true;
--- a/components/search_engines/template_url_service.h
+++ b/components/search_engines/template_url_service.h
@@ -706,6 +706,8 @@ class TemplateURLService : public WebDat
   // ---------- Browser state related members ---------------------------------
   PrefService* prefs_ = nullptr;
 
+  bool should_autocollect_; // Whether search engines should be auto-collected
+
   std::unique_ptr<SearchTermsData> search_terms_data_ =
       std::make_unique<SearchTermsData>();