I'm using Firefox since version circa 1.5 and I think some of your arguments regarding "very important features Google introduced." are slightly off:
> Draggable, swappable tabs
I cannot recall Firefox lacked such feature. You can even swap tabs without mouse (ctrl+shift+pgUp/Down) what is not possible in Chrome AFAIK. And you have slightly greater control over order and appearance of tabs in Firefox.
> [..] that can be pulled out into separate windows,
Pulling tabs from / to Chrome windows is FMPoW UX disaster against proven patterns, at least in Windows platform [1]
> [..] address bars with integrated search engines,
AFaIR Mozilla experimented with "Awesomebar" way before Google Chrome Omnibar appeared. Things like accelerator searches and keyword bookmarks were there since its dawn. It was just "ease of use and lack of control" that Chrome introduced. [2]
> [..] built in PDF viewer[s].
Frankly, I don't have data who had integrated plugin-less PDF viewer first. Yes, it might have been considerable advantage.
[1] usually you can dragNdrop anything between any two windows using the "delayed hover on taskbar" mechanism: e.g. with Firefox you
1) drag the item (tab) from the source window (dragging cursor / icon appears),
2) hover on taskbar item of target window (window appears), and
3) drop the tab among other tabs in target window.
In Chrome you must
1) choose (focus) the target window first,
2) switch to source window,
3) drag the tab (source window disappears completely, revealing target window under some weird temporal tab/window that sticks to target or could be dropped to create own new window) and
4) drop tab among other tabs in the target window.
[2] as expressed in other comments, some users preferes adress bar to primarily consume just URLS and for search use isolated input. Vanilla Firefox Quantum can be set like this today, and you can have your search bar hidden in overflow menu but still one keyboard shortcut away.
> Draggable, swappable tabs
I cannot recall Firefox lacked such feature. You can even swap tabs without mouse (ctrl+shift+pgUp/Down) what is not possible in Chrome AFAIK. And you have slightly greater control over order and appearance of tabs in Firefox.
> [..] that can be pulled out into separate windows,
Pulling tabs from / to Chrome windows is FMPoW UX disaster against proven patterns, at least in Windows platform [1]
> [..] address bars with integrated search engines,
AFaIR Mozilla experimented with "Awesomebar" way before Google Chrome Omnibar appeared. Things like accelerator searches and keyword bookmarks were there since its dawn. It was just "ease of use and lack of control" that Chrome introduced. [2]
> [..] built in PDF viewer[s].
Frankly, I don't have data who had integrated plugin-less PDF viewer first. Yes, it might have been considerable advantage.
[1] usually you can dragNdrop anything between any two windows using the "delayed hover on taskbar" mechanism: e.g. with Firefox you 1) drag the item (tab) from the source window (dragging cursor / icon appears), 2) hover on taskbar item of target window (window appears), and 3) drop the tab among other tabs in target window.
In Chrome you must 1) choose (focus) the target window first, 2) switch to source window, 3) drag the tab (source window disappears completely, revealing target window under some weird temporal tab/window that sticks to target or could be dropped to create own new window) and 4) drop tab among other tabs in the target window.
[2] as expressed in other comments, some users preferes adress bar to primarily consume just URLS and for search use isolated input. Vanilla Firefox Quantum can be set like this today, and you can have your search bar hidden in overflow menu but still one keyboard shortcut away.