Run dartfmt on all files under runtime.

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

Index: runtime/observatory/lib/src/elements/heap_snapshot.dart
diff --git a/runtime/observatory/lib/src/elements/heap_snapshot.dart b/runtime/observatory/lib/src/elements/heap_snapshot.dart
index 830e1a0b7229551cb0b4827237d7011df01a20d3..025a1da6c376b2d12e49610c980547d33c6ae047 100644
--- a/runtime/observatory/lib/src/elements/heap_snapshot.dart
+++ b/runtime/observatory/lib/src/elements/heap_snapshot.dart
@@ -140,9 +140,7 @@ class HeapSnapshotElement extends HtmlElement implements Renderable {
 
   Future _refresh() async {
     _progress = null;
-    _progressStream = _snapshots.get(isolate,
-                                     roots: _roots,
-                                     gc: true);
+    _progressStream = _snapshots.get(isolate, roots: _roots, gc: true);
     _r.dirty();
     _progressStream.listen((e) {
       _progress = e.progress;
@@ -281,14 +279,13 @@ class HeapSnapshotElement extends HtmlElement implements Renderable {
         ]);
         break;
       case HeapSnapshotTreeMode.mergedDominatorTree:
-        _tree = new VirtualTreeElement(
-            _createMergedDominator, _updateMergedDominator,
-            _getChildrenMergedDominator,
+        _tree = new VirtualTreeElement(_createMergedDominator,
+            _updateMergedDominator, _getChildrenMergedDominator,
             items: _getChildrenMergedDominator(_snapshot.mergedDominatorTree),
             queue: _r.queue);
         _tree.expand(_snapshot.mergedDominatorTree);
         final text = 'A heap dominator tree, where siblings with the same class'
-                     ' have been merged into a single node.';
+            ' have been merged into a single node.';
         report.addAll([
           new DivElement()
             ..classes = ['content-centered-big', 'explanation']
@@ -376,6 +373,7 @@ class HeapSnapshotElement extends HtmlElement implements Renderable {
         .where((child) => child.retainedSize >= kMinRetainedSize)
         .take(kMaxChildren);
   }
+
   static _getChildrenMergedDominator(M.HeapSnapshotMergedDominatorNode node) {
     final list = node.children.toList();
     list.sort((a, b) => b.retainedSize - a.retainedSize);
@@ -414,8 +412,7 @@ class HeapSnapshotElement extends HtmlElement implements Renderable {
       wrapper
         ..text = ''
         ..children = [
-          new AnchorElement(href: Uris.debugger(isolate))
-            ..text = 'stack frames'
+          new AnchorElement(href: Uris.debugger(isolate))..text = 'stack frames'
         ];
     } else {
       node.object.then((object) {
@@ -445,8 +442,7 @@ class HeapSnapshotElement extends HtmlElement implements Renderable {
       wrapper
         ..text = ''
         ..children = [
-          new AnchorElement(href: Uris.debugger(isolate))
-            ..text = 'stack frames'
+          new AnchorElement(href: Uris.debugger(isolate))..text = 'stack frames'
         ];
     } else {
       node.klass.then((klass) {