Disable the SyzyASan instrumentation of chrome_child.dll for the official builds.

chrome/chrome_syzygy.gyp

 # 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.
 {
   'conditions': [
     ['OS=="win" and fastbuild==0', {
       'variables': {
         'dll_name': 'chrome',
       },
       'targets': [
         {
           'target_name': 'chrome_dll_syzygy',
           'type': 'none',
           'sources' : [],
           'includes': [
             'chrome_syzygy.gypi',
           ],
         },
       ],
     }],
     # Note, not else.
-    ['OS=="win" and fastbuild==0 and chrome_multiple_dll==1', {
+    ['OS=="win" and fastbuild==0 and chrome_multiple_dll==1 and '
+        '(asan!=1 or buildtype!="Official")', {
       'variables': {
         'dll_name': 'chrome_child',
       },
       'targets': [
         {
           'target_name': 'chrome_child_dll_syzygy',
           'type': 'none',
           'sources' : [],
           'includes': [
             'chrome_syzygy.gypi',
           ],
         },
       ],
+    }, {
+      'conditions': [
+        ['OS=="win" and fastbuild==0 and chrome_multiple_dll==1 and '

[gab, 2013/09/10 18:27:02]

Feels like this would be cleaner if:

1) The condition on line 22 was only 'OS=="win" and fastbuild==0 and
chrome_multiple_dll==1'.
2) It had an internal condition '(asan!=1 or buildtype!="Official"'
3) This was the else block of that condition.

[Sébastien Marchand, 2013/09/10 18:58:56]

Yeah, Chris is working on another CL that'll change all of this. See my response
to your other comment for the details.

+            'asan==1 and buildtype=="Official"', {
+          'targets': [
+          {
+            'target_name': 'chrome_child_dll_syzygy',
+            'type': 'none',
+            'inputs': [
+              '<(PRODUCT_DIR)/chrome_child.dll',
+              '<(PRODUCT_DIR)/chrome_child.dll.pdb',
+            ],
+            'outputs': [
+              '<(PRODUCT_DIR)/syzygy/chrome_child.dll',
+              '<(PRODUCT_DIR)/syzygy/chrome_child.dll.pdb',
+            ],
+            'copies': [
+              {
+                'destination': '<(PRODUCT_DIR)/syzygy',
+                'files': [
+                  '<(PRODUCT_DIR)/chrome_child.dll',
+                  '<(PRODUCT_DIR)/chrome_child.dll.pdb',
+                ],

[gab, 2013/09/10 18:27:02]

Which doesn't the main chrome DLL need to do this copy?

[gab, 2013/09/10 18:27:32]

s/Which/Why

[Sébastien Marchand, 2013/09/10 18:58:56]

The purpose of this CL was to be able to run an experiment where only chrome.dll
is SyzyASan-instrumented. This allow us to ship a Canary/Dev build where only
the browser is instrumented, so the user experience is not impacted too much.

We're having a pretty good coverage for the renderer processes with Clusterfuzz,
but not so much for the browser, it's why we're interested in running this kind
of experiment.

Chris is working on a cleaner CL. He want to export fine-grained control for
each library with 'asan_chrome_dll' and 'asan_chrome_child_dll' variables, with
default values for those variables based on the value of asan and buildtype.

+              },
+            ],
+          }],
+        }],
+      ],
     }],
   ],
 }