One of the internal pages of Google Chrome- Chrome://Memory, which redirects to Chrome://Memory-redirect has been removed by Chromium team. The page that displays Chrome memory usage, including those of extensions, apps and web pages, is also displays memory consumption of all running browsers. You can see this change on latest Chrome developer,  that is on version 51.

This page can also be opened by clicking the ‘stats for nerds’ link on Chrome task manager window (that one now is missing as a result of this). While the reason for deleting Chrome://memory page is still unknown, but the bug closed by Chrome team gives the following the description or information for killing the page.

Chrome memory redirect page

This page is going to be removed from Chrome internal pages list sooner or later

“This deletes the majority of the code supporting chrome://memory pages. There’s still a little bit more of follow-up work to clean up
memory_details*.cc files, but those will require some changes to logic and thus is better to do them in a separate CL”.

From the above statement, we can confirm that chrome://memory-internals was also gone from dev. version.