Added secondary /MergeSession verification step.

We will now inspect outcome of /ListAccounts call to check if the primary
session SID/LSID cookies got run over by browser session restore process.

For now, the outcome of this test is just reported as a UMA histogram.

BUG=309131
TEST=none

Review URL: https://codereview.chromium.org/103463003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239385 0039d316-1c4b-4281-b951-d872f2087c98
Check for NOT_A_DIRECTORY error in remote to local syncer

TEST=Automated. Added RemoteToLocalSyncerTest.Conflict_CreateNestedFolderOnFile
BUG=240165

Review URL: https://codereview.chromium.org/104503002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239386 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 239386
Gin: Make it easier to implement Wrappable.

BUG=

Review URL: https://codereview.chromium.org/105743007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239387 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 239387