[Sync] Cleanup all tab sync enabling logic now that its on by default.

BUG=none
TEST=


Review URL: https://chromiumcodereview.appspot.com/10443046

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@139462 0039d316-1c4b-4281-b951-d872f2087c98
  void ExpectLocalOrderIsByServerId() {
    ReadTransaction trans(FROM_HERE, directory());
    Id null_id;
    Entry low(&trans, GET_BY_ID, low_id_);
    Entry mid(&trans, GET_BY_ID, mid_id_);
    Entry high(&trans, GET_BY_ID, high_id_);
    EXPECT_TRUE(low.good());
    EXPECT_TRUE(mid.good());
    EXPECT_TRUE(high.good());
    EXPECT_TRUE(low.Get(PREV_ID) == null_id);
    EXPECT_TRUE(mid.Get(PREV_ID) == low_id_);
    EXPECT_TRUE(high.Get(PREV_ID) == mid_id_);
    EXPECT_TRUE(high.Get(NEXT_ID) == null_id);
    EXPECT_TRUE(mid.Get(NEXT_ID) == high_id_);
    EXPECT_TRUE(low.Get(NEXT_ID) == mid_id_);
  }

  void ExpectLocalOrderIsByServerId() {
    ReadTransaction trans(FROM_HERE, directory());
    Id null_id;
    Entry low(&trans, GET_BY_ID, low_id_);
    Entry mid(&trans, GET_BY_ID, mid_id_);
    Entry high(&trans, GET_BY_ID, high_id_);
    EXPECT_TRUE(low.good());
    EXPECT_TRUE(mid.good());
    EXPECT_TRUE(high.good());
    EXPECT_TRUE(low.Get(PREV_ID) == null_id);
    EXPECT_TRUE(mid.Get(PREV_ID) == low_id_);
    EXPECT_TRUE(high.Get(PREV_ID) == mid_id_);
    EXPECT_TRUE(high.Get(NEXT_ID) == null_id);
    EXPECT_TRUE(mid.Get(NEXT_ID) == high_id_);
    EXPECT_TRUE(low.Get(NEXT_ID) == mid_id_);
  }
