Send untruncated dart:developer logs to debugging clients

[elliette]

Creating a DWDS-specific issue from flutter/devtools#3222

• Currently, dart:developer uses the console.log web API for developer.log: https://github.com/dart-lang/sdk/blob/7933cd741d01239367c58f9a384a2bad4a086c4f/sdk/lib/_internal/js_dev_runtime/patch/developer_patch.dart#L70
• By default, Chrome truncates any console.log messages over a certain character limit (you can view the untruncated message by clicking the expand arrow in Chrome DevTools
• However, when DWDS reads from the console.log stream, it is getting only the truncated messages:

  webdev/dwds/lib/src/services/chrome_proxy_service.dart

  Line 1243 in 4d1de26

  /// Returns a streamController that listens for console logs from chrome and

• This means that when DWDS forwards those messages to debugging clients (e.g. Flutter DevTools) those clients only have access to the truncated message

Some options:

1. Is there some way to get the non-truncated console.log messages from Chrome's log stream?

2. If not, we can use emitDebugEvent in devleoper_patch to send messages to DWDS instead of console.logging them (this is what dart-lang/sdk@c83eeac did for postEvent). This is the proposal here: Flutter Web truncates logs written with dart:developer flutter/devtools#3222 (comment)

[annagrin]

There is an old issue for this with links to the ones in the sdk: #1619