Switch "Downloads" directory path to the per-profile ones for multi-profile support.

All migration code has already landed. This is the final CL that carries out the switch.
By this CL, Files.app in multi-profile session starts showing each profile's Downloads folder,
not the primary profile's one. This is a transient state for the future fully-multiprofile-aware
Files.app (ETA: M34) that shows all profile's folder in a single window.

The following is the summary/background why the path switch is needed:

We had used /home/chronos/user/Download as the path to the "Downloads" folder for all users.
This does not hold for multi-profile session. The "real" path for multiple users are
/home/chronos/u-unique-hash-userA/Downloads
/home/chronos/u-unique-hash-userB/Downloads
...
and /home/chronos/user is just an alias to the user who first signed into the session.

To make all user's folder available simultaneously in one multi-profile session,
we need to stop using the alias, and differentiate all folders by the real path.

BUG=309556

Review URL: https://codereview.chromium.org/48903012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243794 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 243794
Android: Add support for returning real screen resolution.

This is supported since JB-MR1, and doesn't subtract
window decorations etc. like other size metrics do.

TBR=yfriedman@chromium.org
BUG=329439

Review URL: https://codereview.chromium.org/93933016

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243795 0039d316-1c4b-4281-b951-d872f2087c98
Override cache policy when changing a reload to a back/forward navigation.

In some cases, the RenderView performs a history navigation in response to a
reload when the WebFrame does not have the page in question committed. Override
the cache policy so the navigation revalidates the cache, rather than skipping
revalidation altogether.

BUG=331386
TEST=CrashRecoveryBrowserTest.ReloadCacheRevalidate

Review URL: https://codereview.chromium.org/101203007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243796 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 243796