Switch how we track whether trackDdcProfile is set to reduce the performance impact. sra was seeing…

lib/runtime/dart_sdk.js

Index: lib/runtime/dart_sdk.js
diff --git a/lib/runtime/dart_sdk.js b/lib/runtime/dart_sdk.js
index a1c927671592c7aaea7d06a1cdf6b8f7655b021e..45afbe05969c6d98d99fc81ee768e511cd51a8da 100644
--- a/lib/runtime/dart_sdk.js
+++ b/lib/runtime/dart_sdk.js
@@ -1100,7 +1100,7 @@ dart_library.library('dart_sdk', null, /* Imports */[
     dart._callMethodStats[dartx.clear]();
   };
   dart._trackCall = function(obj, name) {
-    if (!dart.global.trackDdcProfile) return;
+    if (!dart.trackProfile) return;
     let actual = dart.getReifiedType(obj);
     let stackStr = new Error().stack;
     let stack = stackStr[dartx.split]('\n    at ');
@@ -1885,6 +1885,12 @@ dart_library.library('dart_sdk', null, /* Imports */[
     },
     set _callMethodStats(_) {}
   });
+  dart.defineLazy(dart, {
+    get trackProfile() {
+      return dart.global.trackDdcProfile;
+    },
+    set trackProfile(_) {}
+  });
   dart._ignoreTypeFailure = (() => {
     return dart._ignoreMemo((actual, type) => {
       if (!!dart.isSubtype(type, core.Iterable) && !!dart.isSubtype(actual, core.Iterable) || !!dart.isSubtype(type, async.Future) && !!dart.isSubtype(actual, async.Future) || !!dart.isSubtype(type, core.Map) && !!dart.isSubtype(actual, core.Map) || dart.isFunctionType(type) && dart.isFunctionType(actual) || !!dart.isSubtype(type, async.Stream) && !!dart.isSubtype(actual, async.Stream) || !!dart.isSubtype(type, async.StreamSubscription) && !!dart.isSubtype(actual, async.StreamSubscription)) {