Linux: Add support for chrooted renderers.

base/process_util_linux.cc

Index: base/process_util_linux.cc
diff --git a/base/process_util_linux.cc b/base/process_util_linux.cc
index ed8d32d0ffacf1f7e4554baa2174c5a977dfdc11..b68ef025301f62776f6c96a46d49779d32a6dfbb 100644
--- a/base/process_util_linux.cc
+++ b/base/process_util_linux.cc
@@ -60,6 +60,11 @@ bool LaunchApp(const std::vector<std::string>& argv,
 
     CloseSuperfluousFds(fd_shuffle);
 
+    // If we are using the SUID sandbox, it sets a magic environment variable
+    // ("SBX_D"), so we remove that variable from the environment here on the
+    // off chance that it's already set.
+    unsetenv("SBX_D");
+
     scoped_array<char*> argv_cstr(new char*[argv.size() + 1]);
     for (size_t i = 0; i < argv.size(); i++)
       argv_cstr[i] = const_cast<char*>(argv[i].c_str());