Track when profiles are last used.

This will allow use to ignore profiles unused for a certain length of time (likely 28 days) when calculating statistics on number of profiles, number of signed-in profiles, etc.

BUG=295817

Review URL: https://codereview.chromium.org/134863002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244760 0039d316-1c4b-4281-b951-d872f2087c98
Reduce binary size impact of synthetic delays

This patch reduces the binary size impact of synthetic delays. Namely:

  1. Use strtod() instead of base::StringToDouble. Saves 12K on x64 for
     targets that did not already use base::StringToDouble (e.g.,
     nacl_helper).
  2. Use std::vector<std::string> instead of
     std::vector<std::pair<std::string, std::string>>. Saves 5K.

The remaining binary size impact for the feature is about 6K.

BUG=307841,333373
TEST=TraceEventTestFixture.*Delay*

Review URL: https://codereview.chromium.org/136723006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244761 0039d316-1c4b-4281-b951-d872f2087c98
[DevTools] Fix DCHECK hitting on DevTools reload.

Browser assumed that WebContents must be in TabStripModel,
while docked DevTools is not.

BUG=none
TEST=Open docked DevTools, hit Alt+R, nothing bad happens.

Review URL: https://codereview.chromium.org/136863002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244762 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 244762