TL;DR: I finally found what cause this bug in Windows 7 (and surely in all other Windows versions). Actually it's about GDI Objects.
When the number of GDI Object reaches 10 000, the bug appears and Chrome crashes few times after. Now, I jut wonder if it's a bug in Chrome or if it's a plugin / extension bug.
To see GDI Objects in Task manager, click in menu "Display" → "select columns..." → check "GDI Object" checkbox.
I experienced this kind of bug with IE (v7 i think, or 6 perhaps) on Windows XP SP3.
I experienced it with Chrome too but only with Windows 7 Home Premium.
I do not think anti-virus are a cause of this, because I got this problem on a fresh laptop (bought last month) with an official Windows 7 Home Premium installed on it, and I never installed any anti-virus by now... (even installed and removed!)
How this bug appeared for me:
First, I never had hundreds of tabs opened when this "bug" appeared but each time, the browser was running for a long time (with many tabs opened and closed). It was the same thing with IE.
When I tried to download anything (similar problem opening a new tab), the "save" dialog box did not appear (not enough GUI handles?). The browser seemed to be frozen but when I moved another window on the top of Chrome I could guess the save-dialog-box's frame/borders because there were refresh bugs. So the dialog-box was not displayed but it was "shown" anyway. I eventually pressed escape and the dialog-box closed and browser "unfroze.
Currently my browser, Iron (a Chrome-like browser based on Chromium) has 31 tabs opened, the process that owns the majority of handles has 29203 handles, the second process has 2667 handles, then explorer.exe has 1392 handles, etc. And I have no GUI handle problem.
When I had this problem, Iron had around 7000 handles only, so it does not make sense to think it's a handle problem or any handle leak that browsers could manage badly.
I think it's a problem with Windows.. maybe a handle recycling system, I don't know.
Note: When I had this problem on Windows 7, I ran Task Manager, and it is displayed correctly. On Windows XP (with IE), not on this laptop, Task Manager had the problem too. I could not see any any process because the grid with processes and columns was not displayed! Actually I could not run any program on this computer until I closed IE and released all handles.
On Windows 7 (with Chrome issue), GUI handle ressources seem to be isolated because I could see Task Manager and run any other program without this GUI handle starvation / shortage.
The GUI handle problem is confined to Iron.
Since I never had this problem with Iron on Windows XP, this issue could be because of plugins.