Run dartfmt on all files under runtime.

runtime/observatory/lib/src/repositories/heap_snapshot.dart

Index: runtime/observatory/lib/src/repositories/heap_snapshot.dart
diff --git a/runtime/observatory/lib/src/repositories/heap_snapshot.dart b/runtime/observatory/lib/src/repositories/heap_snapshot.dart
index a4f90b31777ca534ee43dffd9e6e8aef00ce0e60..cea60e295f551b3f0a2c61a0aad2995931d55f34 100644
--- a/runtime/observatory/lib/src/repositories/heap_snapshot.dart
+++ b/runtime/observatory/lib/src/repositories/heap_snapshot.dart
@@ -100,10 +100,8 @@ class HeapSnapshotLoadingProgress extends M.HeapSnapshotLoadingProgress {
 }
 
 class HeapSnapshotRepository implements M.HeapSnapshotRepository {
-  Stream<HeapSnapshotLoadingProgressEvent> get(
-      M.IsolateRef i,
-      {M.HeapSnapshotRoots roots: M.HeapSnapshotRoots.vm,
-      bool gc: false}) {
+  Stream<HeapSnapshotLoadingProgressEvent> get(M.IsolateRef i,
+      {M.HeapSnapshotRoots roots: M.HeapSnapshotRoots.vm, bool gc: false}) {
     S.Isolate isolate = i as S.Isolate;
     assert(isolate != null);
     assert(gc != null);