Bug 1357002 - Part 1: Cache "dom.webcomponents.customelements.enabled" preference; r=wchen

MozReview-Commit-ID: HMsvOmYJvjX

dom/base/CustomElementRegistry.cpp

@@ -172,7 +172,7 @@ NS_INTERFACE_MAP_END
 /* static */ bool
 CustomElementRegistry::IsCustomElementEnabled(JSContext* aCx, JSObject* aObject)
 {
-  return Preferences::GetBool("dom.webcomponents.customelements.enabled") ||
+  return nsContentUtils::IsCustomElementsEnabled() ||
          nsContentUtils::IsWebComponentsEnabled();
 }
 

dom/base/nsContentUtils.cpp

@@ -291,6 +291,7 @@ bool nsContentUtils::sIsResourceTimingEnabled = false;
 bool nsContentUtils::sIsUserTimingLoggingEnabled = false;
 bool nsContentUtils::sIsExperimentalAutocompleteEnabled = false;
 bool nsContentUtils::sIsWebComponentsEnabled = false;
+bool nsContentUtils::sIsCustomElementsEnabled = false;
 bool nsContentUtils::sPrivacyResistFingerprinting = false;
 bool nsContentUtils::sSendPerformanceTimingNotifications = false;
 bool nsContentUtils::sUseActivityCursor = false;
@@ -596,6 +597,9 @@ nsContentUtils::Init()
   Preferences::AddBoolVarCache(&sIsWebComponentsEnabled,
                                "dom.webcomponents.enabled", false);
 
+  Preferences::AddBoolVarCache(&sIsCustomElementsEnabled,
+                               "dom.webcomponents.customelements.enabled", false);
+
   Preferences::AddBoolVarCache(&sPrivacyResistFingerprinting,
                                "privacy.resistFingerprinting", false);
 

dom/base/nsContentUtils.h

@@ -2863,6 +2863,9 @@ public:
   static already_AddRefed<nsIEventTarget>
   GetEventTargetByLoadInfo(nsILoadInfo* aLoadInfo, mozilla::TaskCategory aCategory);
 
+  static bool
+  IsCustomElementsEnabled() { return sIsCustomElementsEnabled; }
+
 private:
   static bool InitializeEventTable();
 
@@ -2980,6 +2983,7 @@ private:
   static bool sIsFrameTimingPrefEnabled;
   static bool sIsExperimentalAutocompleteEnabled;
   static bool sIsWebComponentsEnabled;
+  static bool sIsCustomElementsEnabled;
   static bool sPrivacyResistFingerprinting;
   static bool sSendPerformanceTimingNotifications;
   static bool sUseActivityCursor;

dom/ipc/ContentPrefs.cpp

@@ -64,6 +64,7 @@ const char* mozilla::dom::ContentPrefs::gInitPrefs[] = {
   "dom.vibrator.enabled",
   "dom.vibrator.max_vibrate_list_len",
   "dom.vibrator.max_vibrate_ms",
+  "dom.webcomponents.customelements.enabled",
   "dom.webcomponents.enabled",
   "focusmanager.testmode",
   "font.size.inflation.disabledInMasterProcess",