ScriptCat 应处理 Frozen Tab 问题 （保留中） #1028

1. 打开 https://example.com/?test_discard
2. 打开 chrome://discards/
3. 找 https://example.com/?test_discard 然后 [Urgent Discard] / [Freeze]

Discarded Tab:

Frozen Tab:

❄️ Frozen Tab

A frozen tab is still fully loaded in memory, but Chrome pauses its JavaScript execution (timers, events, content scripts) to save resources.

Behavior when sending a message:

• Chrome does attempt to deliver the message to the tab.
• However, because the tab’s JavaScript is paused, the content script cannot run immediately.
• When the tab is later unfrozen (e.g., becomes active), the content script will resume and then process the message.

Callback behavior:

• The callback or promise resolution may be significantly delayed, depending on when the tab is unfrozen.

• No error is thrown simply because the tab is frozen.

  • The message does not immediately fail.
  • It simply waits on the tab to resume execution.

Unfreezing:

• Happens when:

  • The tab becomes the active tab, or
  • Chrome decides to resume it automatically.

• In very recent Chrome versions (M124+), if the tab stays frozen for an extremely long time and the message queue grows too large, Chrome may eventually drop messages silently, but this is rare and still no error is thrown.

🗑️ Discarded Tab

A discarded tab is completely unloaded from memory. Its renderer process is gone, though the tab still appears in the tab strip with title + favicon.

Behavior when sending a message:

*When you send a message to a discarded tab:

• Chrome detects immediately that there is no renderer → fails instantly.
• The callback is invoked immediately with an error.

Reloading:

• The tab reloads its page (and content scripts) when the user activates it.

✅ Summary

如果是 Discard, 网页会重载，所以消息可以直接不发
如果是 Frozen，因为网页解冻时会接收堆叠了的消息，使用上不影响，但做法似乎不太合适
(Chrome 124＋ 有机会直接放弃堆叠了的消息）

目前想法：
discard 放弃不管。等reload
unfreeze 情况的话，SC自行堆叠。等下次 sendMessage 时放回去