Revise user-data-dir switch handling; avoid crashes.

Chrome needs a pre-existing or creatable user-data-dir to run.
ChromeMainDelegate::PreSandboxStartup was CHECK'ing for this.
(crashing on startup with --user-data-dir="M:\invalid")
(crashing on startup with --user-data-dir="C:\windows")

Supposedly, we had a dialog to let users choose another dir.
(I've never gotten this to work on M28-M32 stable versions)

Revise the user-data-dir code to warn on invalid paths.
(see crbug.com/318999#c18 for the warning screenshot)
Then attempt to use the default directory as a backup.
(no alternate dir selection UI, users can try again)

This should avoid many of the numerous related crashes.

BUG=318999
TEST=Supplying an invalid --user-data-dir=<path> will warn users and attempt to use the default directory instead of silently crashing.
R=sky@chromium.org

Review URL: https://codereview.chromium.org/123693003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251126 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251126
cc: add more devtools instrumentation

This adds didRequestMainThreadFrame() and didDrawFrame() so we can better
track impl-side frame lifecycle in DevTools

R=danakj, nduca

Review URL: https://codereview.chromium.org/144463016

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251127 0039d316-1c4b-4281-b951-d872f2087c98
Use the new animation tween types to improve the animation effects for app list folder operation.

BUG=342832

Review URL: https://codereview.chromium.org/162363002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251128 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251128