[linux] remove dependency between nacl_helper and media

content/common/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//content/common/common.gni")
 import("//media/media_options.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 import("//tools/ipc_fuzzer/ipc_fuzzer.gni")
@@ skipping 206 matching lines @@
 
   if (enable_ipc_fuzzer) {
     configs += [ "//tools/ipc_fuzzer:ipc_fuzzer_config" ]
     sources += [
       "external_ipc_dumper.cc",
       "external_ipc_dumper.h",
     ]
   }
 }
 
+if (is_linux) {
+  # This target contains sources from //content/common needed by nacl_helper.
+  # It does not depend on //media/ffmpeg unlike //content/common.
+  # So nacl_helper executable does not crash when cannot find libbffmpeg.so.
+  source_set("sandbox_linux") {
+    sources = [
+      "//content/public/common/child_process_sandbox_support_linux.h",

[Mark Seaborn, 2016/08/31 18:28:04]

This is duplicating too much in the GN build to handle a case that's not tested
by the Chromium bots (i.e. overriding libffmpeg via LD_LIBRARY_PATH).

Can you find a simpler way to achieve this?

For example, content_switches.cc is currently referenced by
content/public/common/BUILD.gn.  It's not good to be adding a reference to a
different BUILD.gn file.  But content/public/common/BUILD.gn already defines a
separate target for it, so you can reference that target rather than duplicating
the reference here.

Maybe you could do the same for the other files?  Where are these other files
currently referenced from?  What currently pulls in the media dependency that
you want to remove?

+      "//content/public/common/content_switches.cc",
+      "//content/public/common/content_switches.h",
+      "//content/public/common/main_function_params.h",
+      "//content/public/common/sandbox_init.h",
+      "//content/public/common/sandbox_linux.h",
+      "//content/public/common/sandbox_type.h",
+      "//content/public/common/sandboxed_process_launcher_delegate.cc",
+      "//content/public/common/sandboxed_process_launcher_delegate.h",
+      "//content/public/common/send_zygote_child_ping_linux.h",
+      "//content/public/common/zygote_fork_delegate_linux.h",
+      "//content/public/common/zygote_handle.h",
+      "child_process_sandbox_support_impl_linux.cc",
+      "child_process_sandbox_support_impl_linux.h",
+      "child_process_sandbox_support_impl_shm_linux.cc",
+      "content_export.h",
+      "sandbox_linux/sandbox_debug_handling_linux.cc",
+      "sandbox_linux/sandbox_debug_handling_linux.h",
+      "sandbox_linux/sandbox_init_linux.cc",
+      "sandbox_linux/sandbox_linux.cc",
+      "sandbox_linux/sandbox_linux.h",
+      "send_zygote_child_ping_linux.cc",
+      "set_process_title.cc",
+      "set_process_title.h",
+      "set_process_title_linux.cc",
+      "set_process_title_linux.h",
+      "zygote_commands_linux.h",
+    ]
+    deps = [
+      "//base",
+      "//content/public/common:content_descriptors",
+      "//ipc:ipc",
+      "//ppapi/c:c",
+      "//sandbox/linux:sandbox_services",
+      "//sandbox/linux:suid_sandbox_client",
+      "//third_party/WebKit/public:blink_headers",
+      "//third_party/WebKit/public:blink_minimal",
+    ]
+    if (use_seccomp_bpf) {
+      defines = [ "USE_SECCOMP_BPF" ]
+      sources += [
+        "sandbox_linux/bpf_cros_arm_gpu_policy_linux.cc",
+        "sandbox_linux/bpf_cros_arm_gpu_policy_linux.h",
+        "sandbox_linux/bpf_gpu_policy_linux.cc",
+        "sandbox_linux/bpf_gpu_policy_linux.h",
+        "sandbox_linux/bpf_ppapi_policy_linux.cc",
+        "sandbox_linux/bpf_ppapi_policy_linux.h",
+        "sandbox_linux/bpf_renderer_policy_linux.cc",
+        "sandbox_linux/bpf_renderer_policy_linux.h",
+        "sandbox_linux/bpf_utility_policy_linux.cc",
+        "sandbox_linux/bpf_utility_policy_linux.h",
+        "sandbox_linux/sandbox_bpf_base_policy_linux.cc",
+        "sandbox_linux/sandbox_bpf_base_policy_linux.h",
+        "sandbox_linux/sandbox_seccomp_bpf_linux.cc",
+        "sandbox_linux/sandbox_seccomp_bpf_linux.h",
+      ]
+      deps += [
+        "//sandbox/linux:seccomp_bpf",
+        "//ui/gl:switches",
+      ]
+      if (is_android) {
+        sources += [
+          "sandbox_linux/android/sandbox_bpf_base_policy_android.cc",
+          "sandbox_linux/android/sandbox_bpf_base_policy_android.h",
+        ]
+      }
+    }
+  }
+}
+
 # See comment at the top of //content/BUILD.gn for how this works.
 group("for_content_tests") {
   visibility = [ "//content/test/*" ]
   if (!is_component_build) {
     public_deps = [
       ":common",
     ]
   }
 }
 
@@ skipping 25 matching lines @@
     "//third_party/WebKit/public:mojo_bindings",
     "//ui/gfx/geometry/mojo",
     "//url/mojo:url_mojom_gurl",
     "//url/mojo:url_mojom_origin",
   ]
 
   export_class_attribute = "CONTENT_EXPORT"
   export_define = "CONTENT_IMPLEMENTATION=1"
   export_header = "content/common/content_export.h"
 }