Use the DefaultSearchManager as the exclusive authority on DSE, ignoring Web Data.

chrome/test/data/policy/policy_test_cases.json

 {
   "-- Template --": {
     "intro": "Top-level entries map a policy name to its test parameters, described below.",
 
     "os": ["List of operating systems that support this policy. Valid values:", "win", "linux", "mac", "chromeos", "Defaults to empty if not specified."],
     "official_only": "Whether this policy exists in official builds only. Defaults to |false| if not specified.",
     "can_be_recommended": "Whether a recommended value may be set for the policy. Defaults to |false| if not specified.",
     "test_policy": "A policy dictionary that should make the preferences affected by this policy become policy-controlled. Usually just sets the current policy. Defaults to an empty dictionary if not specified.",
     "note": "If the policy affects any preferences, the following array should be specified with one entry per such preference.",
     "pref_mappings": [
@@ skipping 721 matching lines @@
           { "policy": { "BlockThirdPartyCookies": true } }
         ]
       }
     ]
   },
 
   "DefaultSearchProviderEnabled": {
     "os": ["win", "linux", "mac", "chromeos"],
     "test_policy": { "DefaultSearchProviderEnabled": false },
     "pref_mappings": [
-      { "pref": "default_search_provider.enabled",
+      { "pref": "default_search_provider_data.template_url_data",
         "indicator_tests": [
           { "policy": { "DefaultSearchProviderEnabled": false } },
           { "policy": { "DefaultSearchProviderEnabled": true, "DefaultSearchProviderSearchURL": "http://www.google.com/?q={searchTerms}", "DefaultSearchProviderKeyword": "google" } }
         ]
       }
     ]
   },
 
   "DefaultSearchProviderName": {
     "os": ["win", "linux", "mac", "chromeos"],
     "test_policy": { "DefaultSearchProviderSearchURL": "http://www.google.com/?q={searchTerms}", "DefaultSearchProviderKeyword": "google", "DefaultSearchProviderName": "google.com" },
     "pref_mappings": [
-      { "pref": "default_search_provider.name" }
+      { "pref": "default_search_provider_data.template_url_data" }
     ]
   },
 
   "DefaultSearchProviderKeyword": {
     "os": ["win", "linux", "mac", "chromeos"],
     "test_policy": { "DefaultSearchProviderSearchURL": "http://www.google.com/?q={searchTerms}", "DefaultSearchProviderKeyword": "google" },
     "pref_mappings": [
-      { "pref": "default_search_provider.keyword" }
+      { "pref": "default_search_provider_data.template_url_data" }
     ]
   },
 
   "DefaultSearchProviderSearchURL": {
     "os": ["win", "linux", "mac", "chromeos"],
     "test_policy": { "DefaultSearchProviderSearchURL": "http://www.google.com/?q={searchTerms}", "DefaultSearchProviderKeyword": "google" },
     "pref_mappings": [
-      { "pref": "default_search_provider.search_url",
+      { "pref": "default_search_provider_data.template_url_data",
         "indicator_selector": "[setting=search-engine]",
         "indicator_tests": [
           { "policy": { "DefaultSearchProviderEnabled": true, "DefaultSearchProviderSearchURL": "http://www.google.com/?q={searchTerms}" } }
         ]
       }
     ]
   },
 
   "DefaultSearchProviderSuggestURL": {
     "os": ["win", "linux", "mac", "chromeos"],
     "test_policy": { "DefaultSearchProviderSearchURL": "http://www.google.com/?q={searchTerms}", "DefaultSearchProviderKeyword": "google", "DefaultSearchProviderSuggestURL": "http://www.google.com/suggest?q={searchTerms}" },
     "pref_mappings": [
-      { "pref": "default_search_provider.suggest_url" }
+      { "pref": "default_search_provider_data.template_url_data" }
     ]
   },
 
   "DefaultSearchProviderInstantURL": {
     "os": ["win", "linux", "mac", "chromeos"],
     "test_policy": { "DefaultSearchProviderSearchURL": "http://www.google.com/?q={searchTerms}", "DefaultSearchProviderKeyword": "google", "DefaultSearchProviderInstantURL": "http://www.google.com/instant?q={searchTerms}" },
     "pref_mappings": [
-      { "pref": "default_search_provider.instant_url" }
+      { "pref": "default_search_provider_data.template_url_data" }
     ]
   },
 
   "DefaultSearchProviderNewTabURL": {
     "os": ["win", "linux", "mac", "chromeos"],
     "test_policy": { "DefaultSearchProviderSearchURL": "http://www.google.com/?q={searchTerms}", "DefaultSearchProviderKeyword": "google", "DefaultSearchProviderNewTabURL": "http://www.google.com/newtab" },
     "pref_mappings": [
-      { "pref": "default_search_provider.new_tab_url" }
+      { "pref": "default_search_provider_data.template_url_data" }
     ]
   },
 
   "DefaultSearchProviderIconURL": {
     "os": ["win", "linux", "mac", "chromeos"],
     "test_policy": { "DefaultSearchProviderSearchURL": "http://www.google.com/?q={searchTerms}", "DefaultSearchProviderKeyword": "google", "DefaultSearchProviderIconURL": "http://www.google.com/favicon.ico" },
     "pref_mappings": [
-      { "pref": "default_search_provider.icon_url" }
+      { "pref": "default_search_provider_data.template_url_data" }
     ]
   },
 
   "DefaultSearchProviderEncodings": {
     "os": ["win", "linux", "mac", "chromeos"],
     "test_policy": { "DefaultSearchProviderSearchURL": "http://www.google.com/?q={searchTerms}", "DefaultSearchProviderKeyword": "google", "DefaultSearchProviderEncodings": ["UTF-8"] },
     "pref_mappings": [
-      { "pref": "default_search_provider.encodings" }
+      { "pref": "default_search_provider_data.template_url_data" }
     ]
   },
 
   "DefaultSearchProviderAlternateURLs": {
     "os": ["win", "linux", "mac", "chromeos"],
     "test_policy": { "DefaultSearchProviderSearchURL": "http://www.google.com/?q={searchTerms}", "DefaultSearchProviderKeyword": "google", "DefaultSearchProviderAlternateURLs": ["http://www.google.com/#q={searchTerms}", "http://www.google.com/search#q={searchTerms}"] },
     "pref_mappings": [
-      { "pref": "default_search_provider.alternate_urls" }
+      { "pref": "default_search_provider_data.template_url_data" }
     ]
   },
 
   "DefaultSearchProviderSearchTermsReplacementKey": {
     "os": ["win", "linux", "mac", "chromeos"],
     "test_policy": { "DefaultSearchProviderSearchURL": "http://www.google.com/?q={searchTerms}", "DefaultSearchProviderKeyword": "google", "DefaultSearchProviderSearchTermsReplacementKey": "espv" },
     "pref_mappings": [
-      { "pref": "default_search_provider.search_terms_replacement_key" }
+      { "pref": "default_search_provider_data.template_url_data" }
     ]
   },
 
   "DefaultSearchProviderImageURL": {
     "os": ["win", "linux", "mac", "chromeos"],
     "test_policy": { "DefaultSearchProviderSearchURL": "http://www.google.com/?q={searchTerms}", "DefaultSearchProviderKeyword": "google", "DefaultSearchProviderImageURL": "http://www.google.com/searchbyimage/upload" },
     "pref_mappings": [
-      { "pref": "default_search_provider.image_url" }
+      { "pref": "default_search_provider_data.template_url_data" }
     ]
   },
 
   "DefaultSearchProviderSearchURLPostParams": {
     "os": ["win", "linux", "mac", "chromeos"],
     "test_policy": { "DefaultSearchProviderSearchURL": "http://www.google.com/?q={searchTerms}", "DefaultSearchProviderKeyword": "google", "DefaultSearchProviderSearchURLPostParams": "" },
     "pref_mappings": [
-      { "pref": "default_search_provider.search_url_post_params" }
+      { "pref": "default_search_provider_data.template_url_data" }
     ]
   },
 
   "DefaultSearchProviderSuggestURLPostParams": {
     "os": ["win", "linux", "mac", "chromeos"],
     "test_policy": { "DefaultSearchProviderSearchURL": "http://www.google.com/?q={searchTerms}", "DefaultSearchProviderKeyword": "google", "DefaultSearchProviderSuggestURLPostParams": "" },
     "pref_mappings": [
-      { "pref": "default_search_provider.suggest_url_post_params" }
+      { "pref": "default_search_provider_data.template_url_data" }
     ]
   },
 
   "DefaultSearchProviderInstantURLPostParams": {
     "os": ["win", "linux", "mac", "chromeos"],
     "test_policy": { "DefaultSearchProviderSearchURL": "http://www.google.com/?q={searchTerms}", "DefaultSearchProviderKeyword": "google", "DefaultSearchProviderInstantURLPostParams": "" },
     "pref_mappings": [
-      { "pref": "default_search_provider.instant_url_post_params" }
+      { "pref": "default_search_provider_data.template_url_data" }
     ]
   },
 
   "DefaultSearchProviderImageURLPostParams": {
     "os": ["win", "linux", "mac", "chromeos"],
     "test_policy": { "DefaultSearchProviderSearchURL": "http://www.google.com/?q={searchTerms}", "DefaultSearchProviderKeyword": "google", "DefaultSearchProviderImageURLPostParams": "image_content={imageThumbnail},image_url={imageURL},sbisrc={imageSearchSource}" },
     "pref_mappings": [
-      { "pref": "default_search_provider.image_url_post_params" }
+      { "pref": "default_search_provider_data.template_url_data" }
     ]
   },
 
   "DefaultCookiesSetting": {
     "os": ["win", "linux", "mac", "chromeos"],
     "test_policy": { "DefaultCookiesSetting": 2 },
     "pref_mappings": [
       { "pref": "profile.managed_default_content_settings.cookies",
         "indicator_selector": "[content-setting=cookies]",
         "indicator_tests": [
@@ skipping 1391 matching lines @@
 
   "AdditionalLaunchParameters": {
   },
 
   "SuppressChromeFrameTurndownPrompt": {
   },
 
   "SkipMetadataCheck": {
   }
 }