Retry 3 to split WebGraphicsContext3DCommandBufferImpl::initialize() into two stages.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index a64ab3758b89dce365e87ec33c771897d1100b83..496b6155ec012799bb2dbd4e53ec08ad0dbf49a4 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -177,6 +177,9 @@
       # Remoting compilation is enabled by default. Set to 0 to disable.
       'remoting%': 1,
 
+      # Threaded compositing
+      'use_threaded_compositing%': 0,
+
       # P2P APIs are compiled in by default. Set to 0 to disable.
       # Also note that this should be enabled for remoting to compile.
       'p2p_apis%': 1,
@@ -319,6 +322,7 @@
     'use_titlecase_in_grd_files%': '<(use_titlecase_in_grd_files)',
     'use_third_party_translations%': '<(use_third_party_translations)',
     'remoting%': '<(remoting)',
+    'use_threaded_compositing%': '<(use_threaded_compositing)',
     'enable_webrtc%': '<(enable_webrtc)',
     'p2p_apis%': '<(p2p_apis)',
     'configuration_policy%': '<(configuration_policy)',
@@ -820,6 +824,9 @@
       ['remoting==1', {
         'defines': ['ENABLE_REMOTING=1'],
       }],
+      ['use_threaded_compositing==1', {
+        'defines': ['WTF_USE_THREADED_COMPOSITING'],
+      }],
       ['p2p_apis==1', {
         'defines': ['ENABLE_P2P_APIS=1'],
       }],
@@ -833,6 +840,7 @@
         'defines': ['ENABLE_CONFIGURATION_POLICY'],
       }],
       ['fastbuild!=0', {
+
         'conditions': [
           # For Windows, we don't genererate debug information.
           ['OS=="win"', {