Add histograms that track how long it takes to open the new tab page.

Add histograms that track how long it takes to open the new tab page.

This doesn't time all loads of the new tab page, just new foreground
tabs using ctrl+t or the plus button.  This includes the time it takes
to create the tab contents and logs the time until JS has started
executing, domcontentloaded, and onload.

Note: onload doesn't mean the page is done loading.  We have "NewTabUI load" for that.

BUG=23120
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=27918

[tony, 2009-10-01 22:42:41]

Oh, I should add that if someone uses ctrl+t, this doesn't include the time it
takes to go through the current renderer and see if the renderer wants to handle
it.

[jam, 2009-10-02 00:47:49]

lgtm

http://codereview.chromium.org/242107/diff/1/3
File chrome/browser/dom_ui/new_tab_ui.cc (right):

http://codereview.chromium.org/242107/diff/1/3#newcode779
Line 779: }void MostVisitedHandler::AddPinnedURL(const MostVisitedPage& page,
int index) {
nit: accidental delete?

[arv (Not doing code reviews), 2009-10-02 01:24:52]

LGTM

http://codereview.chromium.org/242107/diff/6001/6006
File chrome/browser/tab_contents/tab_contents.cc (right):

http://codereview.chromium.org/242107/diff/6001/6006#newcode1181
Line 1181: UMA_HISTOGRAM_TIMES("NewTab.ScriptStart", duration);
Why don't we send these strings from the client. We should probably still verify
that we got what we wanted though.

[tony, 2009-10-02 23:28:04]

Ok, updated to use the NewTab.* in the js code as well.