Issue 4804 - Avoid trashing pagemaps prematurely

chrome/ext/background.js

Index: chrome/ext/background.js
diff --git a/chrome/ext/background.js b/chrome/ext/background.js
index 7dbcf02812944155504a9a0b377d1476eb4f295a..718585dc34d471779ca85579faa15eac8f3d0ee3 100644
--- a/chrome/ext/background.js
+++ b/chrome/ext/background.js
@@ -129,8 +129,6 @@
     {
       let page = new Page({id: tabId, url: url});
 
-      ext._removeFromAllPageMaps(tabId);

[kzar, 2017/01/18 08:12:09]

I can't see why to remove the tabId from the pageMaps at this point.
- New tabs including prerendered ones get a new tab ID.
- Closed tabs will be removed by our chrome.tabs.onRemoved listener
- Replaced tabs (prerendered tab committed to) will be removed by our
chrome.tabs.onReplaced listener.

Do I miss something?

[Sebastian Noack, 2017/01/18 11:58:31]

The Page and PageMap objects abstract the concept of pages/documents, not tabs.
So if an existing tab loads a new page/document, this is meant to be a different
Page object.

For some of our logic, the distinction between pages and tabs is irrelevant.
However, for the recorded frame hierarchy it is crucial to reset the state when
a tab navigates to a new page/document.

Once we got rid of ext.*, and ext.PageMap in particular, we can just use regular
Map objects with the tabId as key, and clear the frame hierarchy manually. While
the icon animation can use its own data structure which persists the tabs.

Addressing this issue while we still use ext.* is probably not trivial, and
would require adding more complexity to the abtraction layer. So I suggest to
revist this issue later.

-
       chrome.tabs.get(tabId, function()
       {
         // If the tab is prerendered, chrome.tabs.get() sets