Run dartfmt on all files under runtime.

runtime/observatory/tests/observatory_ui/mocks/objects/heap_snapshot.dart

Index: runtime/observatory/tests/observatory_ui/mocks/objects/heap_snapshot.dart
diff --git a/runtime/observatory/tests/observatory_ui/mocks/objects/heap_snapshot.dart b/runtime/observatory/tests/observatory_ui/mocks/objects/heap_snapshot.dart
index 1763ba3bb6976b13cae321a85f36b0afb1e5a56d..d0b268d6a5300f567e47c108874cdd220258715c 100644
--- a/runtime/observatory/tests/observatory_ui/mocks/objects/heap_snapshot.dart
+++ b/runtime/observatory/tests/observatory_ui/mocks/objects/heap_snapshot.dart
@@ -12,8 +12,11 @@ class HeapSnapshotMock implements M.HeapSnapshot {
   final M.HeapSnapshotDominatorNode dominatorTree;
   final Iterable<M.HeapSnapshotClassReferences> classReferences;
 
-  const HeapSnapshotMock({this.timestamp, this.objects: 0,
-      this.references: 0, this.size: 0,
+  const HeapSnapshotMock(
+      {this.timestamp,
+      this.objects: 0,
+      this.references: 0,
+      this.size: 0,
       this.dominatorTree: const HeapSnapshotDominatorNodeMock(),
       this.classReferences: const []});
 }
@@ -24,9 +27,11 @@ class HeapSnapshotDominatorNodeMock implements M.HeapSnapshotDominatorNode {
   final Future<M.ObjectRef> object;
   final Iterable<M.HeapSnapshotDominatorNode> children;
 
-  const HeapSnapshotDominatorNodeMock({this.shallowSize: 1,
-                                       this.retainedSize: 1,
-                                       this.object, this.children: const []});
+  const HeapSnapshotDominatorNodeMock(
+      {this.shallowSize: 1,
+      this.retainedSize: 1,
+      this.object,
+      this.children: const []});
 }
 
 class HeapSnapshotClassReferencesMock implements M.HeapSnapshotClassReferences {
@@ -37,11 +42,13 @@ class HeapSnapshotClassReferencesMock implements M.HeapSnapshotClassReferences {
   final Iterable<M.HeapSnapshotClassInbound> inbounds;
   final Iterable<M.HeapSnapshotClassOutbound> outbounds;
 
-  const HeapSnapshotClassReferencesMock({this.clazz: const ClassRefMock(),
-                                         this.instances: 1, this.shallowSize: 1,
-                                         this.retainedSize: 2,
-                                         this.inbounds: const [],
-                                         this.outbounds: const []});
+  const HeapSnapshotClassReferencesMock(
+      {this.clazz: const ClassRefMock(),
+      this.instances: 1,
+      this.shallowSize: 1,
+      this.retainedSize: 2,
+      this.inbounds: const [],
+      this.outbounds: const []});
 }
 
 class HeapSnapshotClassInboundMock implements M.HeapSnapshotClassInbound {
@@ -50,9 +57,11 @@ class HeapSnapshotClassInboundMock implements M.HeapSnapshotClassInbound {
   final int shallowSize;
   final int retainedSize;
 
-  const HeapSnapshotClassInboundMock({this.source: const ClassRefMock(),
-                                      this.count: 1, this.shallowSize: 1,
-                                      this.retainedSize: 2});
+  const HeapSnapshotClassInboundMock(
+      {this.source: const ClassRefMock(),
+      this.count: 1,
+      this.shallowSize: 1,
+      this.retainedSize: 2});
 }
 
 class HeapSnapshotClassOutboundMock implements M.HeapSnapshotClassOutbound {
@@ -60,7 +69,9 @@ class HeapSnapshotClassOutboundMock implements M.HeapSnapshotClassOutbound {
   final int count;
   final int shallowSize;
   final int retainedSize;
-  const HeapSnapshotClassOutboundMock({this.target: const ClassRefMock(),
-                                       this.count: 1, this.shallowSize: 1,
-                                       this.retainedSize: 2});
+  const HeapSnapshotClassOutboundMock(
+      {this.target: const ClassRefMock(),
+      this.count: 1,
+      this.shallowSize: 1,
+      this.retainedSize: 2});
 }