Extensions: Only create Web request rules registry if Declarative Web Request is enabled.

extensions/browser/api/declarative/rules_registry_service.cc

Index: extensions/browser/api/declarative/rules_registry_service.cc
diff --git a/extensions/browser/api/declarative/rules_registry_service.cc b/extensions/browser/api/declarative/rules_registry_service.cc
index 8fac46194b625b7973eea6a42b4bb194d41b5845..b687cb3934edebb85e3ad3781b928d91822a02dc 100644
--- a/extensions/browser/api/declarative/rules_registry_service.cc
+++ b/extensions/browser/api/declarative/rules_registry_service.cc
@@ -20,6 +20,8 @@
 #include "extensions/browser/api/web_request/web_request_api.h"
 #include "extensions/browser/extension_registry.h"
 #include "extensions/common/extension.h"
+#include "extensions/common/features/feature_channel.h"
+#include "extensions/common/features/feature_provider.h"
 
 namespace extensions {
 
@@ -74,24 +76,31 @@ void RulesRegistryService::EnsureDefaultRulesRegistriesRegistered(
   if (ContainsKey(rule_registries_, key))
     return;
 
-  // Only cache rules for regular pages.
-  RulesCacheDelegate* web_request_cache_delegate = NULL;

[karandeepb, 2017/02/17 02:07:57]

Wasn't able to find code which relied on the existence of a web request rules
registry.

-  if (rules_registry_id == kDefaultRulesRegistryID) {
-    // Create a RulesCacheDelegate.
-    web_request_cache_delegate =
-        new RulesCacheDelegate(true /*log_storage_init_delay*/);
-    cache_delegates_.push_back(base::WrapUnique(web_request_cache_delegate));
+  // Create a web request rules registry if declarative web request is enabled
+  // on the current channel.
+  const Feature* declarative_web_request =
+      FeatureProvider::GetAPIFeature("declarativeWebRequest");
+  if (declarative_web_request->IsAvailableToChannel(GetCurrentChannel())
+          .is_available()) {
+    // Only cache rules for regular pages.
+    RulesCacheDelegate* web_request_cache_delegate = NULL;

[Devlin, 2017/02/17 19:58:28]

nit: since we're touching this code, update to nullptr

[karandeepb, 2017/02/18 02:00:29]

Done.

+    if (rules_registry_id == kDefaultRulesRegistryID) {
+      // Create a RulesCacheDelegate.
+      web_request_cache_delegate =
+          new RulesCacheDelegate(true /*log_storage_init_delay*/);
+      cache_delegates_.push_back(base::WrapUnique(web_request_cache_delegate));
+    }
+    scoped_refptr<WebRequestRulesRegistry> web_request_rules_registry(
+        new WebRequestRulesRegistry(
+            browser_context_, web_request_cache_delegate, rules_registry_id));
+
+    RegisterRulesRegistry(web_request_rules_registry);
+    content::BrowserThread::PostTask(
+        content::BrowserThread::IO, FROM_HERE,
+        base::Bind(&RegisterToExtensionWebRequestEventRouterOnIO,
+                   browser_context_, rules_registry_id,
+                   web_request_rules_registry));
   }
-  scoped_refptr<WebRequestRulesRegistry> web_request_rules_registry(
-      new WebRequestRulesRegistry(browser_context_, web_request_cache_delegate,
-                                  rules_registry_id));
-
-  RegisterRulesRegistry(web_request_rules_registry);
-  content::BrowserThread::PostTask(
-      content::BrowserThread::IO, FROM_HERE,
-      base::Bind(&RegisterToExtensionWebRequestEventRouterOnIO,
-                 browser_context_, rules_registry_id,
-                 web_request_rules_registry));
 
   // Only create a ContentRulesRegistry for regular pages.
   if (rules_registry_id == kDefaultRulesRegistryID) {