There's a difference between "Chrome put pressure on other vendors" (which is clearly true) and "Chrome kicked off the browser performance wars, especially Javascript" (which is the statement I was responding to upthread).
Chrome obviously put pressure on other vendors in various areas, including performance. What just isn't true is that without Chrome there would have been no JS performance competition. Whether the competition would have been as intense as it ended up being is a debatable counterfactual; I believe it would have been.
One other historical note, since you brought it up: Chrome was first announced publicly Sept 3, 2008. The first public beta of IE 8, with tabs in separate processes, was released on March 5, 2008. These processes ran in a low-privilege sandbox, as in fact did the entire browser starting with IE 7 (released October 2006), on Windows Vista or newer. Chrome did provide the first browser sandbox on Windows XP and non-Windows platforms, which was a big step up, of course. Again, there is a difference here between "introduced a new ground-breaking concept" and "incrementally improved on what was already going on".
Oh, and V8 was clearly considered a "threat" by other browser makers way before Chrome had any market share to speak of, so I'm not sure what your remark about Safari is supposed to mean.