diff --git a/gclient.py b/gclient.py
index c347fcb24..0f895c18f 100755
--- a/gclient.py
+++ b/gclient.py
@@ -716,8 +716,7 @@ class Dependency(gclient_utils.WorkItem, DependencySettings):
     if deps_content:
       try:
         local_scope = gclient_eval.Parse(
-            deps_content, self._get_option('validate_syntax', False),
-            filepath, self.get_vars(), self.get_builtin_vars())
+            deps_content, filepath, self.get_vars(), self.get_builtin_vars())
       except SyntaxError as e:
         gclient_utils.SyntaxErrorToError(filepath, e)
 
@@ -2698,12 +2697,6 @@ def CMDsync(parser, args):
                     help='DEPRECATED: This is a no-op.')
   parser.add_option('-m', '--manually_grab_svn_rev', action='store_true',
                     help='DEPRECATED: This is a no-op.')
-  # TODO(phajdan.jr): Remove validation options once default (crbug/570091).
-  parser.add_option('--validate-syntax', action='store_true', default=True,
-                    help='Validate the .gclient and DEPS syntax')
-  parser.add_option('--disable-syntax-validation', action='store_false',
-                    dest='validate_syntax',
-                    help='Disable validation of .gclient and DEPS syntax.')
   parser.add_option('--no-rebase-patch-ref', action='store_false',
                     dest='rebase_patch_ref', default=True,
                     help='Bypass rebase of the patch ref after checkout.')
@@ -2745,7 +2738,6 @@ CMDupdate = CMDsync
 def CMDvalidate(parser, args):
   """Validates the .gclient and DEPS syntax."""
   options, args = parser.parse_args(args)
-  options.validate_syntax = True
   client = GClient.LoadCurrentConfig(options)
   rv = client.RunOnDeps('validate', args)
   if rv == 0:
diff --git a/gclient_eval.py b/gclient_eval.py
index c41ff398d..13abeb863 100644
--- a/gclient_eval.py
+++ b/gclient_eval.py
@@ -372,44 +372,10 @@ def Exec(content, filename='<unknown>', vars_override=None, builtin_vars=None):
     value = _gclient_eval(node, filename, vars_dict)
     local_scope.SetNode(name, value, node)
 
-  return _GCLIENT_SCHEMA.validate(local_scope)
-
-
-def ExecLegacy(content, filename='<unknown>', vars_override=None,
-               builtin_vars=None):
-  """Executes a DEPS file |content| using exec."""
-  local_scope = {}
-  global_scope = {'Var': lambda var_name: '{%s}' % var_name}
-
-  # If we use 'exec' directly, it complains that 'Parse' contains a nested
-  # function with free variables.
-  # This is because on versions of Python < 2.7.9, "exec(a, b, c)" not the same
-  # as "exec a in b, c" (See https://bugs.python.org/issue21591).
-  eval(compile(content, filename, 'exec'), global_scope, local_scope)
-
-  vars_dict = {}
-  vars_dict.update(local_scope.get('vars', {}))
-  if builtin_vars:
-    vars_dict.update(builtin_vars)
-  if vars_override:
-    vars_dict.update({k: v for k, v in vars_override.items() if k in vars_dict})
-
-  if not vars_dict:
-    return local_scope
-
-  def _DeepFormat(node):
-    if isinstance(node, basestring):
-      return node.format(**vars_dict)
-    elif isinstance(node, dict):
-      return {k.format(**vars_dict): _DeepFormat(v) for k, v in node.items()}
-    elif isinstance(node, list):
-      return [_DeepFormat(elem) for elem in node]
-    elif isinstance(node, tuple):
-      return tuple(_DeepFormat(elem) for elem in node)
-    else:
-      return node
-
-  return _DeepFormat(local_scope)
+  try:
+    return _GCLIENT_SCHEMA.validate(local_scope)
+  except schema.SchemaError as e:
+    raise gclient_utils.Error(str(e))
 
 
 def _StandardizeDeps(deps_dict, vars_dict):
@@ -477,8 +443,7 @@ def UpdateCondition(info_dict, op, new_condition):
     del info_dict['condition']
 
 
-def Parse(content, validate_syntax, filename, vars_override=None,
-          builtin_vars=None):
+def Parse(content, filename, vars_override=None, builtin_vars=None):
   """Parses DEPS strings.
 
   Executes the Python-like string stored in content, resulting in a Python
@@ -487,8 +452,6 @@ def Parse(content, validate_syntax, filename, vars_override=None,
 
   Args:
     content: str. DEPS file stored as a string.
-    validate_syntax: bool. Whether syntax should be validated using the schema
-      defined above.
     filename: str. The name of the DEPS file, or a string describing the source
       of the content, e.g. '<string>', '<unknown>'.
     vars_override: dict, optional. A dictionary with overrides for the variables
@@ -500,10 +463,7 @@ def Parse(content, validate_syntax, filename, vars_override=None,
     A Python dict with the parsed contents of the DEPS file, as specified by the
     schema above.
   """
-  if validate_syntax:
-    result = Exec(content, filename, vars_override, builtin_vars)
-  else:
-    result = ExecLegacy(content, filename, vars_override, builtin_vars)
+  result = Exec(content, filename, vars_override, builtin_vars)
 
   vars_dict = result.get('vars', {})
   if 'deps' in result:
diff --git a/tests/gclient_eval_unittest.py b/tests/gclient_eval_unittest.py
index dfb2813d6..92c9ddfd5 100755
--- a/tests/gclient_eval_unittest.py
+++ b/tests/gclient_eval_unittest.py
@@ -20,6 +20,7 @@ metrics.DISABLE_METRICS_COLLECTION = True
 
 import gclient
 import gclient_eval
+import gclient_utils
 
 
 class GClientEvalTest(unittest.TestCase):
@@ -103,7 +104,7 @@ class ExecTest(unittest.TestCase):
         'invalid assignment: overrides var \'a\'', str(cm.exception))
 
   def test_schema_wrong_type(self):
-    with self.assertRaises(schema.SchemaError):
+    with self.assertRaises(gclient_utils.Error):
       gclient_eval.Exec('include_rules = {}')
 
   def test_recursedeps_list(self):
@@ -787,7 +788,7 @@ class RevisionTest(unittest.TestCase):
 
 
 class ParseTest(unittest.TestCase):
-  def callParse(self, validate_syntax=True, vars_override=None):
+  def callParse(self, vars_override=None):
     return gclient_eval.Parse('\n'.join([
         'vars = {',
         '  "foo": "bar",',
@@ -795,7 +796,7 @@ class ParseTest(unittest.TestCase):
         'deps = {',
         '  "a_dep": "a{foo}b",',
         '}',
-    ]), validate_syntax, '<unknown>', vars_override)
+    ]), '<unknown>', vars_override)
 
   def test_supports_vars_inside_vars(self):
     deps_file = '\n'.join([
@@ -810,16 +811,14 @@ class ParseTest(unittest.TestCase):
         '  },',
         '}',
     ])
-    for validate_syntax in False, True:
-      local_scope = gclient_eval.Parse(
-          deps_file, validate_syntax, '<unknown>', None)
-      self.assertEqual({
-          'vars': {'foo': 'bar',
-                   'baz': '"bar" == "bar"'},
-          'deps': {'src/baz': {'url': 'baz_url',
-                               'dep_type': 'git',
-                               'condition': 'baz'}},
-      }, local_scope)
+    local_scope = gclient_eval.Parse(deps_file, '<unknown>', None)
+    self.assertEqual({
+        'vars': {'foo': 'bar',
+                 'baz': '"bar" == "bar"'},
+        'deps': {'src/baz': {'url': 'baz_url',
+                             'dep_type': 'git',
+                             'condition': 'baz'}},
+    }, local_scope)
 
   def test_has_builtin_vars(self):
     builtin_vars = {'builtin_var': 'foo'}
@@ -828,13 +827,11 @@ class ParseTest(unittest.TestCase):
       '  "a_dep": "a{builtin_var}b",',
       '}',
     ])
-    for validate_syntax in False, True:
-      local_scope = gclient_eval.Parse(
-          deps_file, validate_syntax, '<unknown>', None, builtin_vars)
-      self.assertEqual({
-        'deps': {'a_dep': {'url': 'afoob',
-                           'dep_type': 'git'}},
-      }, local_scope)
+    local_scope = gclient_eval.Parse(deps_file, '<unknown>', None, builtin_vars)
+    self.assertEqual({
+      'deps': {'a_dep': {'url': 'afoob',
+                         'dep_type': 'git'}},
+    }, local_scope)
 
   def test_declaring_builtin_var_has_no_effect(self):
     builtin_vars = {'builtin_var': 'foo'}
@@ -846,14 +843,12 @@ class ParseTest(unittest.TestCase):
         '  "a_dep": "a{builtin_var}b",',
         '}',
     ])
-    for validate_syntax in False, True:
-      local_scope = gclient_eval.Parse(
-          deps_file, validate_syntax, '<unknown>', None, builtin_vars)
-      self.assertEqual({
-        'vars': {'builtin_var': 'bar'},
-        'deps': {'a_dep': {'url': 'afoob',
-                           'dep_type': 'git'}},
-      }, local_scope)
+    local_scope = gclient_eval.Parse(deps_file, '<unknown>', None, builtin_vars)
+    self.assertEqual({
+      'vars': {'builtin_var': 'bar'},
+      'deps': {'a_dep': {'url': 'afoob',
+                         'dep_type': 'git'}},
+    }, local_scope)
 
   def test_override_builtin_var(self):
     builtin_vars = {'builtin_var': 'foo'}
@@ -863,32 +858,28 @@ class ParseTest(unittest.TestCase):
       '  "a_dep": "a{builtin_var}b",',
       '}',
     ])
-    for validate_syntax in False, True:
-      local_scope = gclient_eval.Parse(
-          deps_file, validate_syntax, '<unknown>', vars_override, builtin_vars)
-      self.assertEqual({
-        'deps': {'a_dep': {'url': 'aoverrideb',
-                           'dep_type': 'git'}},
-      }, local_scope, str(local_scope))
+    local_scope = gclient_eval.Parse(
+        deps_file, '<unknown>', vars_override, builtin_vars)
+    self.assertEqual({
+      'deps': {'a_dep': {'url': 'aoverrideb',
+                         'dep_type': 'git'}},
+    }, local_scope, str(local_scope))
 
   def test_expands_vars(self):
-    for validate_syntax in True, False:
-      local_scope = self.callParse(validate_syntax=validate_syntax)
-      self.assertEqual({
-          'vars': {'foo': 'bar'},
-          'deps': {'a_dep': {'url': 'abarb',
-                             'dep_type': 'git'}},
-      }, local_scope)
+    local_scope = self.callParse()
+    self.assertEqual({
+        'vars': {'foo': 'bar'},
+        'deps': {'a_dep': {'url': 'abarb',
+                           'dep_type': 'git'}},
+    }, local_scope)
 
   def test_overrides_vars(self):
-    for validate_syntax in True, False:
-      local_scope = self.callParse(validate_syntax=validate_syntax,
-                                   vars_override={'foo': 'baz'})
-      self.assertEqual({
-          'vars': {'foo': 'bar'},
-          'deps': {'a_dep': {'url': 'abazb',
-                             'dep_type': 'git'}},
-      }, local_scope)
+    local_scope = self.callParse(vars_override={'foo': 'baz'})
+    self.assertEqual({
+        'vars': {'foo': 'bar'},
+        'deps': {'a_dep': {'url': 'abazb',
+                           'dep_type': 'git'}},
+    }, local_scope)
 
   def test_no_extra_vars(self):
     deps_file = '\n'.join([
@@ -901,101 +892,131 @@ class ParseTest(unittest.TestCase):
     ])
 
     with self.assertRaises(KeyError) as cm:
-      gclient_eval.Parse(
-          deps_file, True, '<unknown>', {'baz': 'lalala'})
+      gclient_eval.Parse(deps_file, '<unknown>', {'baz': 'lalala'})
     self.assertIn('baz was used as a variable, but was not declared',
                   str(cm.exception))
 
-    with self.assertRaises(KeyError) as cm:
-      gclient_eval.Parse(
-          deps_file, False, '<unknown>', {'baz': 'lalala'})
-    self.assertIn('baz', str(cm.exception))
-
   def test_standardizes_deps_string_dep(self):
-    for validate_syntax in True, False:
-      local_scope = gclient_eval.Parse('\n'.join([
-        'deps = {',
-        '  "a_dep": "a_url@a_rev",',
-        '}',
-      ]), validate_syntax, '<unknown>')
-      self.assertEqual({
-          'deps': {'a_dep': {'url': 'a_url@a_rev',
-                             'dep_type': 'git'}},
-      }, local_scope)
+    local_scope = gclient_eval.Parse('\n'.join([
+      'deps = {',
+      '  "a_dep": "a_url@a_rev",',
+      '}',
+    ]), '<unknown>')
+    self.assertEqual({
+        'deps': {'a_dep': {'url': 'a_url@a_rev',
+                           'dep_type': 'git'}},
+    }, local_scope)
 
   def test_standardizes_deps_dict_dep(self):
-    for validate_syntax in True, False:
-      local_scope = gclient_eval.Parse('\n'.join([
-        'deps = {',
-        '  "a_dep": {',
-        '     "url": "a_url@a_rev",',
-        '     "condition": "checkout_android",',
-        '  },',
-        '}',
-      ]), validate_syntax, '<unknown>')
-      self.assertEqual({
-          'deps': {'a_dep': {'url': 'a_url@a_rev',
-                             'dep_type': 'git',
-                             'condition': 'checkout_android'}},
-      }, local_scope)
+    local_scope = gclient_eval.Parse('\n'.join([
+      'deps = {',
+      '  "a_dep": {',
+      '     "url": "a_url@a_rev",',
+      '     "condition": "checkout_android",',
+      '  },',
+      '}',
+    ]), '<unknown>')
+    self.assertEqual({
+        'deps': {'a_dep': {'url': 'a_url@a_rev',
+                           'dep_type': 'git',
+                           'condition': 'checkout_android'}},
+    }, local_scope)
 
   def test_ignores_none_in_deps_os(self):
-    for validate_syntax in True, False:
-      local_scope = gclient_eval.Parse('\n'.join([
-        'deps = {',
-        '  "a_dep": "a_url@a_rev",',
-        '}',
-        'deps_os = {',
-        '  "mac": {',
-        '     "a_dep": None,',
-        '  },',
-        '}',
-      ]), validate_syntax, '<unknown>')
-      self.assertEqual({
-          'deps': {'a_dep': {'url': 'a_url@a_rev',
-                             'dep_type': 'git'}},
-      }, local_scope)
+    local_scope = gclient_eval.Parse('\n'.join([
+      'deps = {',
+      '  "a_dep": "a_url@a_rev",',
+      '}',
+      'deps_os = {',
+      '  "mac": {',
+      '     "a_dep": None,',
+      '  },',
+      '}',
+    ]), '<unknown>')
+    self.assertEqual({
+        'deps': {'a_dep': {'url': 'a_url@a_rev',
+                           'dep_type': 'git'}},
+    }, local_scope)
 
   def test_merges_deps_os_extra_dep(self):
-    for validate_syntax in True, False:
-      local_scope = gclient_eval.Parse('\n'.join([
-        'deps = {',
-        '  "a_dep": "a_url@a_rev",',
-        '}',
-        'deps_os = {',
-        '  "mac": {',
-        '     "b_dep": "b_url@b_rev"',
-        '  },',
-        '}',
-      ]), validate_syntax, '<unknown>')
-      self.assertEqual({
-          'deps': {'a_dep': {'url': 'a_url@a_rev',
-                             'dep_type': 'git'},
-                   'b_dep': {'url': 'b_url@b_rev',
-                             'dep_type': 'git',
-                             'condition': 'checkout_mac'}},
-      }, local_scope)
+    local_scope = gclient_eval.Parse('\n'.join([
+      'deps = {',
+      '  "a_dep": "a_url@a_rev",',
+      '}',
+      'deps_os = {',
+      '  "mac": {',
+      '     "b_dep": "b_url@b_rev"',
+      '  },',
+      '}',
+    ]), '<unknown>')
+    self.assertEqual({
+        'deps': {'a_dep': {'url': 'a_url@a_rev',
+                           'dep_type': 'git'},
+                 'b_dep': {'url': 'b_url@b_rev',
+                           'dep_type': 'git',
+                           'condition': 'checkout_mac'}},
+    }, local_scope)
 
   def test_merges_deps_os_existing_dep_with_no_condition(self):
-    for validate_syntax in True, False:
-      local_scope = gclient_eval.Parse('\n'.join([
-        'deps = {',
-        '  "a_dep": "a_url@a_rev",',
-        '}',
-        'deps_os = {',
-        '  "mac": {',
-        '     "a_dep": "a_url@a_rev"',
-        '  },',
-        '}',
-      ]), validate_syntax, '<unknown>')
-      self.assertEqual({
-          'deps': {'a_dep': {'url': 'a_url@a_rev',
-                             'dep_type': 'git'}},
-      }, local_scope)
+    local_scope = gclient_eval.Parse('\n'.join([
+      'deps = {',
+      '  "a_dep": "a_url@a_rev",',
+      '}',
+      'deps_os = {',
+      '  "mac": {',
+      '     "a_dep": "a_url@a_rev"',
+      '  },',
+      '}',
+    ]), '<unknown>')
+    self.assertEqual({
+        'deps': {'a_dep': {'url': 'a_url@a_rev',
+                           'dep_type': 'git'}},
+    }, local_scope)
 
   def test_merges_deps_os_existing_dep_with_condition(self):
-    for validate_syntax in True, False:
-      local_scope = gclient_eval.Parse('\n'.join([
+    local_scope = gclient_eval.Parse('\n'.join([
+      'deps = {',
+      '  "a_dep": {',
+      '    "url": "a_url@a_rev",',
+      '    "condition": "some_condition",',
+      '  },',
+      '}',
+      'deps_os = {',
+      '  "mac": {',
+      '     "a_dep": "a_url@a_rev"',
+      '  },',
+      '}',
+    ]), '<unknown>')
+    self.assertEqual({
+        'deps': {
+            'a_dep': {'url': 'a_url@a_rev',
+                      'dep_type': 'git',
+                      'condition': '(checkout_mac) or (some_condition)'},
+        },
+    }, local_scope)
+
+  def test_merges_deps_os_multiple_os(self):
+    local_scope = gclient_eval.Parse('\n'.join([
+      'deps_os = {',
+      '  "win": {'
+      '     "a_dep": "a_url@a_rev"',
+      '  },',
+      '  "mac": {',
+      '     "a_dep": "a_url@a_rev"',
+      '  },',
+      '}',
+    ]), '<unknown>')
+    self.assertEqual({
+        'deps': {
+            'a_dep': {'url': 'a_url@a_rev',
+                      'dep_type': 'git',
+                      'condition': '(checkout_mac) or (checkout_win)'},
+        },
+    }, local_scope)
+
+  def test_fails_to_merge_same_dep_with_different_revisions(self):
+    with self.assertRaises(gclient_eval.gclient_utils.Error) as cm:
+      gclient_eval.Parse('\n'.join([
         'deps = {',
         '  "a_dep": {',
         '    "url": "a_url@a_rev",',
@@ -1004,76 +1025,31 @@ class ParseTest(unittest.TestCase):
         '}',
         'deps_os = {',
         '  "mac": {',
-        '     "a_dep": "a_url@a_rev"',
+        '     "a_dep": "a_url@b_rev"',
         '  },',
         '}',
-      ]), validate_syntax, '<unknown>')
-      self.assertEqual({
-          'deps': {
-              'a_dep': {'url': 'a_url@a_rev',
-                        'dep_type': 'git',
-                        'condition': '(checkout_mac) or (some_condition)'},
-          },
-      }, local_scope)
-
-  def test_merges_deps_os_multiple_os(self):
-    for validate_syntax in True, False:
-      local_scope = gclient_eval.Parse('\n'.join([
-        'deps_os = {',
-        '  "win": {'
-        '     "a_dep": "a_url@a_rev"',
-        '  },',
-        '  "mac": {',
-        '     "a_dep": "a_url@a_rev"',
-        '  },',
-        '}',
-      ]), validate_syntax, '<unknown>')
-      self.assertEqual({
-          'deps': {
-              'a_dep': {'url': 'a_url@a_rev',
-                        'dep_type': 'git',
-                        'condition': '(checkout_mac) or (checkout_win)'},
-          },
-      }, local_scope)
-
-  def test_fails_to_merge_same_dep_with_different_revisions(self):
-    for validate_syntax in True, False:
-      with self.assertRaises(gclient_eval.gclient_utils.Error) as cm:
-        gclient_eval.Parse('\n'.join([
-          'deps = {',
-          '  "a_dep": {',
-          '    "url": "a_url@a_rev",',
-          '    "condition": "some_condition",',
-          '  },',
-          '}',
-          'deps_os = {',
-          '  "mac": {',
-          '     "a_dep": "a_url@b_rev"',
-          '  },',
-          '}',
-        ]), validate_syntax, '<unknown>')
-      self.assertIn('conflicts with existing deps', str(cm.exception))
+      ]), '<unknown>')
+    self.assertIn('conflicts with existing deps', str(cm.exception))
 
   def test_merges_hooks_os(self):
-    for validate_syntax in True, False:
-      local_scope = gclient_eval.Parse('\n'.join([
-        'hooks = [',
-        '  {',
-        '    "action": ["a", "action"],',
-        '  },',
-        ']',
-        'hooks_os = {',
-        '  "mac": [',
-        '    {',
-        '       "action": ["b", "action"]',
-        '    },',
-        '  ]',
-        '}',
-      ]), validate_syntax, '<unknown>')
-      self.assertEqual({
-          "hooks": [{"action": ["a", "action"]},
-                    {"action": ["b", "action"], "condition": "checkout_mac"}],
-      }, local_scope)
+    local_scope = gclient_eval.Parse('\n'.join([
+      'hooks = [',
+      '  {',
+      '    "action": ["a", "action"],',
+      '  },',
+      ']',
+      'hooks_os = {',
+      '  "mac": [',
+      '    {',
+      '       "action": ["b", "action"]',
+      '    },',
+      '  ]',
+      '}',
+    ]), '<unknown>')
+    self.assertEqual({
+        "hooks": [{"action": ["a", "action"]},
+                  {"action": ["b", "action"], "condition": "checkout_mac"}],
+    }, local_scope)
 
 
 
diff --git a/tests/gclient_test.py b/tests/gclient_test.py
index bd5889a0d..63816944e 100755
--- a/tests/gclient_test.py
+++ b/tests/gclient_test.py
@@ -1002,7 +1002,6 @@ class GclientTest(trial_dir.TestCase):
         '}')
     options, _ = gclient.OptionParser().parse_args([])
     options.ignore_dep_type = 'git'
-    options.validate_syntax = True
     obj = gclient.GClient.LoadCurrentConfig(options)
 
     self.assertEqual(1, len(obj.dependencies))
@@ -1132,7 +1131,7 @@ class GclientTest(trial_dir.TestCase):
       obj.RunOnDeps('None', [])
       self.fail()
     except gclient_utils.Error as e:
-      self.assertIn('allowed_hosts must be', str(e))
+      self.assertIn('Key \'allowed_hosts\' error:', str(e))
     finally:
       self._get_processed()
 
@@ -1160,7 +1159,6 @@ class GclientTest(trial_dir.TestCase):
         '  }\n'
         '}')
     options, _ = gclient.OptionParser().parse_args([])
-    options.validate_syntax = True
     obj = gclient.GClient.LoadCurrentConfig(options)
 
     self.assertEqual(1, len(obj.dependencies))
@@ -1202,7 +1200,6 @@ class GclientTest(trial_dir.TestCase):
         '}')
     options, _ = gclient.OptionParser().parse_args([])
     options.ignore_dep_type = 'cipd'
-    options.validate_syntax = True
     obj = gclient.GClient.LoadCurrentConfig(options)
 
     self.assertEqual(1, len(obj.dependencies))