Flip 'Linux x64' bot on chromium waterfall to GN.

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 791 matching lines @@
       "//gpu:gpu_perftests",
       "//media:media_perftests",
       "//media/midi:midi_unittests",
       "//tools/telemetry:bitmaptools",
     ]
 
     if (!is_chromeos) {
       deps += [ "//chrome/test:performance_browser_tests" ]
     }
     if (is_linux && !is_chromeos) {
-      deps += [ "//chrome:linux_symbols" ]
+      if (is_official_build) {
+        # In GN builds, this is controlled by the 'linux_dump_symbols'
+        # flag, which defaults to 1 for official builds. For now,
+        # we skip the separate flag and just key off of is_official_build.
+        deps += [ "//chrome:linux_symbols" ]
+      }
 
       if (!is_chromeos) {
         deps += [ "//tools/perf/clear_system_cache" ]
       }
     }
 
     if (is_win) {
       deps += [
         "//content/shell:crash_service",
         # "//gpu:angle_perftests", TODO(GYP): crbug.com/537008
       ]
 
       if (target_cpu == "x86") {
         deps += [
           # "//content/shell:crash_service_win64", TODO(GYP): crbug.com/537009
         ]
       }
     } else {
       deps += [ "//breakpad:minidump_stackwalk($host_toolchain)" ]
     }
   }
 }