Fix the //sandbox/mac build when using a modern (10.7+) SDK.

This doesn't use the dynamic library loader if the SDK has libxpc.dylib, and
instead just relies on libSystem to load it.

BUG=395364
R=mark@chromium.org

Review URL: https://codereview.chromium.org/403193002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@284427 0039d316-1c4b-4281-b951-d872f2087c98

sandbox/mac/BUILD.gn

@@ -28,8 +28,15 @@ component("sandbox") {
 
   deps = [
     "//base",
-    ":generate_stubs",
   ]
+
+  # When the build SDK is 10.6, generate a dynamic stub loader. When the
+  # SDK is higher, then libxpc.dylib will be loaded automatically as part
+  # of libSystem, and only forward declarations of private symbols are
+  # necessary.
+  if (mac_sdk_version == "10.6") {
+    deps += [ ":generate_stubs" ]
+  }
 }
 
 generate_stubs_script = "//tools/generate_stubs/generate_stubs.py"

sandbox/mac/sandbox_mac.gypi

@@ -41,6 +41,12 @@
           '$(SDKROOT)/usr/lib/libbsm.dylib',
         ],
       },
+      'conditions': [
+        # When the build SDK is 10.6, generate a dynamic stub loader. When the
+        # SDK is higher, then libxpc.dylib will be loaded automatically as part
+        # of libSystem, and only forward declarations of private symbols are
+        # necessary.
+        ['mac_sdk == "10.6"', {
           'actions': [
             {
               'variables': {
@@ -79,6 +85,8 @@
               'message': 'Generating XPC stubs for 10.6 compatability.',
             },
           ],
+        }],
+      ],
     },
     {
       'target_name': 'sandbox_mac_unittests',

sandbox/mac/xpc.cc

@@ -7,6 +7,8 @@
 namespace sandbox {
 
 bool InitializeXPC() {
+#if !defined(MAC_OS_X_VERSION_10_7) || \
+    MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_7
   std::vector<std::string> path_list;
   path_list.push_back("/usr/lib/system/libxpc.dylib");
 
@@ -15,6 +17,9 @@ bool InitializeXPC() {
   path_map[sandbox_mac::kModuleXpc_private_stubs] = path_list;
 
   return sandbox_mac::InitializeStubs(path_map);
+#else
+  return true;
+#endif
 }
 
 }  // namespace sandbox

sandbox/mac/xpc.h

@@ -10,19 +10,20 @@
 #ifndef SANDBOX_MAC_XPC_H_
 #define SANDBOX_MAC_XPC_H_
 
+#include <AvailabilityMacros.h>
 #include <mach/mach.h>
 
 #include "sandbox/sandbox_export.h"
 
-// C++ library loader.
-#include "sandbox/mac/xpc_stubs.h"
-
 // Declares XPC object types. This includes <xpc/xpc.h> if available.
 #include "sandbox/mac/xpc_stubs_header.fragment"
 
 #if !defined(MAC_OS_X_VERSION_10_7) || \
     MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_7
 
+// C++ library loader.
+#include "sandbox/mac/xpc_stubs.h"
+
 extern "C" {
 // Signatures for XPC public functions that are loaded by xpc_stubs.h.
 #include "sandbox/mac/xpc_stubs.sig"