Revert a temporary workaround for issue 310479, which led to TSan v2 slowdown on the bots.

build/common.gypi

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 3267 matching lines @@
                 ],
               }],
               ['_toolset=="target" and OS=="linux"', {
                 'ldflags': [
                   # http://crbug.com/234010.
                   '-lrt',
                 ],
               }],
             ],
           }],
-          # TODO(glider): this is a temporary workaround for
-          # http://crbug.com/310479.
-          ['tsan==1', {
-            'target_conditions': [
-              ['_toolset=="target"', {
-                'cflags!': [
-                  '-gline-tables-only',
-                ],
-                'cflags': [
-                  '-g',
-                  '-O1',
-                  '-fno-inline-functions',
-                  ' -fno-inline',
-                ],
-              }],
-            ],
-          }],
           ['asan==1', {
             'target_conditions': [
               ['_toolset=="target"', {
                 'cflags': [
                   '-fsanitize=address',
                   '-w',  # http://crbug.com/162783
                 ],
                 'ldflags': [
                   '-fsanitize=address',
                 ],
@@ skipping 1434 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }