Add Syzygy support to Windows GN build.

BUILD.gn

 # Copyright (c) 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.
 
 # This is the root build file for GN. GN will start processing by loading this
 # file, and recursively load all dependencies until all dependencies are either
 # resolved or known not to exist (which will cause the build to fail). So if
 # you add a new build file, there must be some path of dependencies from this
 # file to your new one or GN won't know about it.
 
@@ skipping 55 matching lines @@
 
   deps = [
     "//base:base_unittests",
     "//cc:cc_unittests",
     "//chrome",
     "//chrome/test:browser_tests",
     "//chrome/test:interactive_ui_tests",
     "//chrome/test:sync_integration_tests",
     "//chrome/test:unit_tests",
     "//chrome/test/chromedriver:chromedriver_unittests",
+    "//chrome/tools/build/win/syzygy:chrome_dll_syzygy",

[Dirk Pranke, 2015/07/20 19:29:41]

shouldn't this be under is_win or something?

[brettw, 2015/07/20 22:21:55]

I explicitly made the targets exist in all cases because the conditions where
these do something is rather complicated (not even all the time on Windows).

     "//components:components_browsertests",
     "//components:components_unittests",
     "//content/shell:content_shell",
     "//content/test:content_browsertests",
     "//content/test:content_perftests",
     "//content/test:content_unittests",
     "//crypto:crypto_unittests",
     "//device:device_unittests",
     "//extensions:extensions_browsertests",
     "//extensions:extensions_unittests",
@@ skipping 827 matching lines @@
       "//ui/views:views_unittests",  # TooltipControllerTest failures
       "//ui/wm:wm_unittests",  # PASSES 4/21/2015
       "//url:url_unittests",  # PASSES 4/17/2015
 
       # TODO(GYP) nacl_integration
       # TODO(GYP) telemetry_perf_unittests
       # TODO(GYP) telemetry_unittests
     ]
   }
 }