Bug 940273 - Part 2 - Add a pref to enable Service Worker Cache. r=ehsan

dom/workers/RuntimeService.cpp

@@ -156,6 +156,7 @@ static_assert(MAX_WORKERS_PER_DOMAIN >= 1,
 #endif
 
 #define PREF_DOM_FETCH_ENABLED         "dom.fetch.enabled"
+#define PREF_DOM_CACHES_ENABLED        "dom.caches.enabled"
 #define PREF_WORKERS_LATEST_JS_VERSION "dom.workers.latestJSVersion"
 #define PREF_INTL_ACCEPT_LANGUAGES     "intl.accept_languages"
 
@@ -1778,6 +1779,10 @@ RuntimeService::Init()
                                   WorkerPrefChanged,
                                   PREF_DOM_FETCH_ENABLED,
                                   reinterpret_cast<void *>(WORKERPREF_DOM_FETCH))) ||
+      NS_FAILED(Preferences::RegisterCallbackAndCall(
+                                  WorkerPrefChanged,
+                                  PREF_DOM_CACHES_ENABLED,
+                                  reinterpret_cast<void *>(WORKERPREF_DOM_CACHES))) ||
       NS_FAILED(Preferences::RegisterCallback(LoadRuntimeOptions,
                                               PREF_JS_OPTIONS_PREFIX,
                                               nullptr)) ||
@@ -1967,6 +1972,10 @@ RuntimeService::Cleanup()
         NS_FAILED(Preferences::UnregisterCallback(LoadRuntimeOptions,
                                                   PREF_WORKERS_OPTIONS_PREFIX,
                                                   nullptr)) ||
+        NS_FAILED(Preferences::UnregisterCallback(
+                                  WorkerPrefChanged,
+                                  PREF_DOM_CACHES_ENABLED,
+                                  reinterpret_cast<void *>(WORKERPREF_DOM_CACHES))) ||
         NS_FAILED(Preferences::UnregisterCallback(
                                   WorkerPrefChanged,
                                   PREF_DOM_FETCH_ENABLED,
@@ -2561,6 +2570,12 @@ RuntimeService::WorkerPrefChanged(const char* aPrefName, void* aClosure)
       Preferences::GetBool(PREF_DOM_FETCH_ENABLED, false);
   }
 
+  if (key == WORKERPREF_DOM_CACHES) {
+    key = WORKERPREF_DOM_CACHES;
+    sDefaultPreferences[WORKERPREF_DOM_CACHES] =
+      Preferences::GetBool(PREF_DOM_CACHES_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

@@ -1180,6 +1180,13 @@ public:
     return mPreferences[WORKERPREF_DOM_FETCH];
   }
 
+  bool
+  DOMCachesEnabled() const
+  {
+    AssertIsOnWorkerThread();
+    return mPreferences[WORKERPREF_DOM_CACHES];
+  }
+
   bool
   OnLine() const
   {

dom/workers/Workers.h

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

modules/libpref/init/all.js

@@ -4433,6 +4433,10 @@ pref("camera.control.face_detection.enabled", true);
 
 // Fetch API.
 pref("dom.fetch.enabled", false);
+
+// SW Cache API
+pref("dom.caches.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