Steps to Reproduce

1, Sample code:
new Text("bold: 你好你好55", style: new TextStyle(fontSize: 25.0, fontWeight: FontWeight.bold,)),
new Text("normal: 你好你好55", style: new TextStyle(fontSize: 25.0, fontWeight: FontWeight.normal,)),
2, Got:

Problem:
The Chinese characters in the first line are not bold.

Logs

Flutter Doctor

Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel beta, v0.2.3, on Mac OS X 10.12.6 16G1212, locale zh-Hans-HK)
[✓] Android toolchain - develop for Android devices (Android SDK 27.0.3)
[!] iOS toolchain - develop for iOS devices (Xcode 9.1)
✗ CocoaPods not installed.
CocoaPods is used to retrieve the iOS platform side's plugin code that responds to your plugin usage on the Dart side.
Without resolving iOS dependencies with CocoaPods, plugins will not work on iOS.
For more info, see https://flutter.io/platform-plugins
To install:
brew install cocoapods
pod setup
[✓] Android Studio (version 3.0)
[✓] IntelliJ IDEA Community Edition (version 2017.2.3)
[✓] Connected devices (2 available)

! Doctor found issues in 1 category.
Process finished with exit code 0