Remove "MacImeLiveConversionFix" feature flag

Minor

Commit Hash: 7060fa47866f4cc425ac4a60dc342aae3afa0132

Commit Time: 2025-10-30 14:30:14+00:00

Impact Level: Minor

Generated By: webview2-upstream-sentry

Upstream Review: View Upstream Review 🔗

📋 Summary

This submission removes the "MacImeLiveConversionFix" feature flag and its related implementation, which has already been enabled by default. The feature flag has been enabled by default since version M133 and was used to fix issues with the live conversion functionality of the Japanese IME on macOS. The removal includes: Chrome flag definition, header file declarations, feature checks in implementation code, and feature flag checks in related unit tests. In render_widget_host_view_cocoa.mm, behaviors previously controlled by the feature flag are now default behaviors, including the logic for retriggering conversion and improved implementation for marked text handling.

🎯 Impact Analysis

Since this change only removes the feature flag while retaining its fix logic, the impact on WebView2Mac is positive and limited. WebView2Mac relies on render_widget_host_view_cocoa.mm to handle input method integration on macOS, especially the real-time conversion feature of Japanese input methods. Removing the feature flag means: 1) The real-time conversion fix logic for Japanese input methods is now permanently enabled, providing a more stable input experience; 2) Code complexity is reduced, eliminating conditional compilation branches; 3) All WebView2Mac instances are ensured to have consistent input method behavior. This change does not break existing functionality; on the contrary, it ensures more reliable multilingual input support.

Impacted Classes:

RenderWidgetHostViewCocoa features::kMacImeLiveConversionFix