Run dartfmt on all files under runtime.

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

Index: runtime/observatory/tests/observatory_ui/mocks/objects/context.dart
diff --git a/runtime/observatory/tests/observatory_ui/mocks/objects/context.dart b/runtime/observatory/tests/observatory_ui/mocks/objects/context.dart
index 2f881f5a55064dc11cc3754af2dd760192b1043c..529ac684687938b31201b615ac63348368243828 100644
--- a/runtime/observatory/tests/observatory_ui/mocks/objects/context.dart
+++ b/runtime/observatory/tests/observatory_ui/mocks/objects/context.dart
@@ -20,14 +20,19 @@ class ContextMock implements M.Context {
   final M.Context parentContext;
   final Iterable<M.ContextElement> variables;
 
-  const ContextMock({this.id: 'context-id', this.vmName: 'context-vmName',
-                     this.clazz: const ClassMock(), this.size: 0, this.length,
-                     this.parentContext, this.variables: const []});
+  const ContextMock(
+      {this.id: 'context-id',
+      this.vmName: 'context-vmName',
+      this.clazz: const ClassMock(),
+      this.size: 0,
+      this.length,
+      this.parentContext,
+      this.variables: const []});
 }
 
 class ContextElementMock implements M.ContextElement {
   final GuardedMock<M.InstanceRef> value;
 
-  const ContextElementMock({this.value: const GuardedMock.fromValue(
-      const InstanceRefMock())});
+  const ContextElementMock(
+      {this.value: const GuardedMock.fromValue(const InstanceRefMock())});
 }