Make the blockfile cache an optional build product for chrome target.

net/net.gyp

 # Copyright 2013 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.
 
 {
   'variables': {
     'chromium_code': 1,
 
     'linux_link_kerberos%': 0,
+    'use_blockfile_cache_backend%': 1,
     'use_tracing_cache_backend%': 0,
     'conditions': [
       ['chromeos==1 or embedded==1 or OS=="android" or OS=="ios"', {
         # Disable Kerberos on ChromeOS, Android and iOS, at least for now.
         # It needs configuration (krb5.conf and so on).
         'use_kerberos%': 0,
       }, {  # chromeos == 0 and embedded==0 and OS!="android" and OS!="ios"
         'use_kerberos%': 1,
       }],
       ['OS=="android" and target_arch != "ia32"', {
         # The way the cache uses mmap() is inefficient on some Android devices.
         # If this flag is set, we hackily avoid using mmap() in the disk cache.
         # We are pretty confident that mmap-ing the index would not hurt any
         # existing x86 android devices, but we cannot be so sure about the
         # variety of ARM devices. So enable it for x86 only for now.
         'posix_avoid_mmap%': 1,

[rvargas (doing something else), 2014/02/06 05:09:28]

I think we should either move all backends to a use_foo pattern, or if we are
making an exception to the norm use this pattern and use a negative definition
(as much as I dislike them).

I'm actually thinking about the final #ifdef in the code, not really about the
gyp variables.

       }, {
         'posix_avoid_mmap%': 0,
       }],
       ['OS=="ios"', {
         # Websockets and socket stream are not used on iOS.
         'enable_websockets%': 0,
         # iOS does not use V8.
         'use_v8_in_net%': 0,
         'enable_built_in_dns%': 0,
       }, {
@@ skipping 1289 matching lines @@
           'defines': [
             'ENABLE_BUILT_IN_DNS',
           ]
         }, { # else
           'sources!': [
             'dns/address_sorter_posix.cc',
             'dns/address_sorter_posix.h',
             'dns/dns_client.cc',
           ],
         }],
+        ['use_blockfile_cache_backend==1', {
+          'defines': [
+            'USE_BLOCKFILE_CACHE_BACKEND',
+          ],
+        }, { # use_blockfile_cache_backend == 0
+          'sources/': [ ['exclude', '^disk_cache/v[23]/' ] ]

[rvargas (doing something else), 2014/02/06 05:09:28]

I'm not sure about excluding v3. I've been leaning towards not excluding it
lately.

Also, I don't think in general we use patterns to exclude/include files on gyp
files (other than the platform specific ones). I would have guessed we want to
be absolutely explicit about what files are part of a target. Matching patterns
from cs or similar doesn't work.

[gavinp, 2014/02/09 15:29:37]

Can you expand on that?
What is "cs or similar"?

This pattern works here, because the directory organization was chosen
specifically to support it, though; it is absolutely explicit because placement
in a directory means exactly that.

Explicitly listing carries the downside that there's two lists to keep precisely
in sync.  Someone will get that wrong very quickly if we go to it.

+        }],
         ['use_tracing_cache_backend==1', {
           'defines': [
             'USE_TRACING_CACHE_BACKEND'
           ],
-         }],
+        }],
         ['use_openssl==1', {
             'sources!': [
               'base/crypto_module_nss.cc',
               'base/keygen_handler_nss.cc',
               'base/nss_memio.c',
               'base/nss_memio.h',
               'cert/cert_database_nss.cc',
               'cert/cert_verify_proc_nss.cc',
               'cert/cert_verify_proc_nss.h',
               'cert/ct_log_verifier_nss.cc',
@@ skipping 1827 matching lines @@
             'net_unittests.isolate',
           ],
           'sources': [
             'net_unittests.isolate',
           ],
         },
       ],
     }],
   ],
 }