Bug 1029620 P5 Create dom.fetch.enabled pref, defaulted to false. r=ehsan

dom/workers/RuntimeService.cpp

@@ -151,6 +151,7 @@ static_assert(MAX_WORKERS_PER_DOMAIN >= 1,
 #define PREF_DOM_WINDOW_DUMP_ENABLED "browser.dom.window.dump.enabled"
 #endif
 
+#define PREF_DOM_FETCH_ENABLED         "dom.fetch.enabled"
 #define PREF_WORKERS_LATEST_JS_VERSION "dom.workers.latestJSVersion"
 
 namespace {
@@ -1772,6 +1773,10 @@ RuntimeService::Init()
                                   PREF_DOM_WINDOW_DUMP_ENABLED,
                                   reinterpret_cast<void *>(WORKERPREF_DUMP))) ||
 #endif
+      NS_FAILED(Preferences::RegisterCallbackAndCall(
+                                  WorkerPrefChanged,
+                                  PREF_DOM_FETCH_ENABLED,
+                                  reinterpret_cast<void *>(WORKERPREF_DOM_FETCH))) ||
       NS_FAILED(Preferences::RegisterCallback(LoadRuntimeAndContextOptions,
                                               PREF_JS_OPTIONS_PREFIX,
                                               nullptr)) ||
@@ -1931,6 +1936,10 @@ RuntimeService::Cleanup()
         NS_FAILED(Preferences::UnregisterCallback(LoadRuntimeAndContextOptions,
                                                   PREF_WORKERS_OPTIONS_PREFIX,
                                                   nullptr)) ||
+        NS_FAILED(Preferences::UnregisterCallback(
+                                  WorkerPrefChanged,
+                                  PREF_DOM_FETCH_ENABLED,
+                                  reinterpret_cast<void *>(WORKERPREF_DOM_FETCH))) ||
 #if DUMP_CONTROLLED_BY_PREF
         NS_FAILED(Preferences::UnregisterCallback(
                                   WorkerPrefChanged,
@@ -2481,6 +2490,12 @@ RuntimeService::WorkerPrefChanged(const char* aPrefName, void* aClosure)
   }
 #endif
 
+  if (key == WORKERPREF_DOM_FETCH) {
+    key = WORKERPREF_DOM_FETCH;
+    sDefaultPreferences[WORKERPREF_DOM_FETCH] =
+      Preferences::GetBool(PREF_DOM_FETCH_ENABLED, false);
+  }
+
   // This function should never be registered as a callback for a preference it
   // does not handle.
   MOZ_ASSERT(key != WORKERPREF_COUNT);

dom/workers/WorkerPrivate.h

@@ -1041,6 +1041,13 @@ public:
     return mPreferences[WORKERPREF_DUMP];
   }
 
+  bool
+  DOMFetchEnabled() const
+  {
+    AssertIsOnWorkerThread();
+    return mPreferences[WORKERPREF_DOM_FETCH];
+  }
+
   bool
   OnLine() const
   {

dom/workers/Workers.h

@@ -166,6 +166,7 @@ struct JSSettings
 enum WorkerPreference
 {
   WORKERPREF_DUMP = 0, // browser.dom.window.dump.enabled
+  WORKERPREF_DOM_FETCH,// dom.fetch.enabled
   WORKERPREF_COUNT
 };
 

modules/libpref/src/init/all.js

@@ -4299,6 +4299,9 @@ pref("beacon.enabled", true);
 // Camera prefs
 pref("camera.control.autofocus_moving_callback.enabled", true);
 pref("camera.control.face_detection.enabled", true);
+
+// Fetch API.
+pref("dom.fetch.enabled", false);
 #ifdef MOZ_WIDGET_GONK
 // Empirically, this is the value returned by hal::GetTotalSystemMemory()
 // when Flame's memory is limited to 512MiB. If the camera stack determines