Move dart2js entrypoint detection into isPrimary.

pkg/scheduled_test/test/scheduled_stream/stream_matcher_test.dart

Index: pkg/scheduled_test/test/scheduled_stream/stream_matcher_test.dart
diff --git a/pkg/scheduled_test/test/scheduled_stream/stream_matcher_test.dart b/pkg/scheduled_test/test/scheduled_stream/stream_matcher_test.dart
index 93c6b43cf4d02309417e15d5e33690f95e1a03b9..d7127443d0e50b94277bd7c31205ea5660f56779 100644
--- a/pkg/scheduled_test/test/scheduled_stream/stream_matcher_test.dart
+++ b/pkg/scheduled_test/test/scheduled_stream/stream_matcher_test.dart
@@ -183,23 +183,25 @@ void main(_, message) {
   expectTestPasses("consumeThrough() consumes values through the given matcher",
       () {
     var stream = createStream();
-    stream.expect(consumeThrough(greaterThan(2)));
+    stream.expect(consumeThrough(inOrder([2, 3])));
     stream.expect(4);
   });
 
   expectTestPasses("consumeThrough() will stop if the first value matches", () {
     var stream = createStream();
-    stream.expect(consumeThrough(1));
-    stream.expect(2);
+    stream.expect(consumeThrough(inOrder([1, 2])));
+    stream.expect(3);
   });
 
   expectTestFails("consumeThrough() will fail if the stream ends before the "
       "value is reached", () {
-    createStream().expect(consumeThrough(100));
+    createStream().expect(consumeThrough(inOrder([5, 6])));
   }, (errors) {
     expect(errors, hasLength(1));
     expect(errors.first.error.message, equals(
-        "Expected: values followed by <100>\n"
+        "Expected: values followed by:\n"
+        "        |   * <5>\n"
+        "        |   * <6>\n"
         " Emitted: * 1\n"
         "          * 2\n"
         "          * 3\n"
@@ -215,10 +217,16 @@ void main(_, message) {
     stream.expect(4);
   });
 
+  expectTestPasses("consumeWhile() consumes values in chunks", () {
+    var stream = createStream();
+    stream.expect(consumeWhile(inOrder([anything, anything])));
+    stream.expect(5);
+  });
+
   expectTestPasses("consumeWhile() will stop if the first value doesn't match",
       () {
     var stream = createStream();
-    stream.expect(consumeWhile(2));
+    stream.expect(consumeWhile(inOrder([2, 3])));
     stream.expect(1);
   });