Make much of the proxy thread-safe with 1 great big lock.

build/common.gypi

 # Copyright (c) 2011 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 206 matching lines @@
 
       # Enable Web Intents and supporting UI.
       'enable_web_intents%': 0,
 
       # Smooth scrolling is disabled by default.
       'enable_smooth_scrolling%': 0,
 
       # Webrtc compilation is enabled by default. Set to 0 to disable.
       'enable_webrtc%': 1,
 
+      # PPAPI by default does not support plugins making calls off the main
+      # thread. Set to 1 to turn on experimental support for out-of-process
+      # plugins to make call of the main thread.
+      'enable_pepper_threading%': 0,
+
       # XInput2 multitouch support is disabled by default (use_xi2_mt=0).
       # Setting to non-zero value enables XI2 MT. When XI2 MT is enabled,
       # the input value also defines the required XI2 minor minimum version.
       # For example, use_xi2_mt=2 means XI2.2 or above version is required.
       'use_xi2_mt%': 0,
 
       # Use of precompiled headers on Windows is off by default
       # because of complications that it can cause with our
       # infrastructure (trybots etc.).  Enable by setting to 1 in
       # ~/.gyp/include.gypi or via the GYP command line for ~20-25%
@@ skipping 111 matching lines @@
     'use_openssl%': '<(use_openssl)',
     'use_nss%': '<(use_nss)',
     'os_posix%': '<(os_posix)',
     'use_glib%': '<(use_glib)',
     'toolkit_uses_gtk%': '<(toolkit_uses_gtk)',
     'use_skia%': '<(use_skia)',
     'use_x11%': '<(use_x11)',
     'use_gnome_keyring%': '<(use_gnome_keyring)',
     'linux_fpic%': '<(linux_fpic)',
     'enable_flapper_hacks%': '<(enable_flapper_hacks)',
+    'enable_pepper_threading%': '<(enable_pepper_threading)',
     'chromeos%': '<(chromeos)',
     'touchui%': '<(touchui)',
     'use_virtual_keyboard%': '<(use_virtual_keyboard)',
     'use_xi2_mt%':'<(use_xi2_mt)',
     'file_manager_extension%': '<(file_manager_extension)',
     'webui_task_manager%': '<(webui_task_manager)',
     'inside_chromium_build%': '<(inside_chromium_build)',
     'fastbuild%': '<(fastbuild)',
     'dcheck_always_on%': '<(dcheck_always_on)',
     'python_ver%': '<(python_ver)',
@@ skipping 603 matching lines @@
       }],
       ['p2p_apis==1', {
         'defines': ['ENABLE_P2P_APIS=1'],
       }],
       ['proprietary_codecs==1', {
         'defines': ['USE_PROPRIETARY_CODECS'],
       }],
       ['enable_flapper_hacks==1', {
         'defines': ['ENABLE_FLAPPER_HACKS=1'],
       }],
+      ['enable_pepper_threading==1', {
+        'defines': ['ENABLE_PEPPER_THREADING'],
+      }],
       ['configuration_policy==1', {
         'defines': ['ENABLE_CONFIGURATION_POLICY'],
       }],
       ['fastbuild!=0', {
 
         'conditions': [
           # For Windows and Mac, we don't genererate debug information.
           ['OS=="win" or OS=="mac"', {
             'msvs_settings': {
               'VCLinkerTool': {
@@ skipping 1508 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',
   },
 }