[scheduler] Add TaskQueue::Observer

third_party/WebKit/Source/platform/scheduler/base/real_time_domain.cc

Index: third_party/WebKit/Source/platform/scheduler/base/real_time_domain.cc
diff --git a/third_party/WebKit/Source/platform/scheduler/base/real_time_domain.cc b/third_party/WebKit/Source/platform/scheduler/base/real_time_domain.cc
index 7406dc4b21d654f8b1da39f5fcb646fb1e446504..434d8a5755a5295bf65be5be53b1bc86c91ed8c6 100644
--- a/third_party/WebKit/Source/platform/scheduler/base/real_time_domain.cc
+++ b/third_party/WebKit/Source/platform/scheduler/base/real_time_domain.cc
@@ -13,15 +13,7 @@ namespace blink {
 namespace scheduler {
 
 RealTimeDomain::RealTimeDomain(const char* tracing_category)
-    : TimeDomain(nullptr),
-      tracing_category_(tracing_category),
-      task_queue_manager_(nullptr) {}
-
-RealTimeDomain::RealTimeDomain(TimeDomain::Observer* observer,
-                               const char* tracing_category)
-    : TimeDomain(observer),
-      tracing_category_(tracing_category),
-      task_queue_manager_(nullptr) {}
+    : tracing_category_(tracing_category), task_queue_manager_(nullptr) {}
 
 RealTimeDomain::~RealTimeDomain() {}