Pass StatsTable shared memory via global descriptors on Posix rather than using named shared memory.

chrome/nacl/nacl_helper_linux.cc

Index: chrome/nacl/nacl_helper_linux.cc
diff --git a/chrome/nacl/nacl_helper_linux.cc b/chrome/nacl/nacl_helper_linux.cc
index e823b5350b98e397aecb3e11e7be666e8077b710..a533c50f80910f4067934b93e00655208ce1b171 100644
--- a/chrome/nacl/nacl_helper_linux.cc
+++ b/chrome/nacl/nacl_helper_linux.cc
@@ -77,8 +77,9 @@ void ChildNaClLoaderInit(const std::vector<int>& child_fds,
   // should not fork any child processes (which the seccomp
   // sandbox does) until then, because that can interfere with the
   // parent's discovery of our PID.
-  const int nread = HANDLE_EINTR(read(child_fds[kNaClParentFDIndex], buffer,
-                                      kMaxReadSize));
+  const int nread = HANDLE_EINTR(
+      read(child_fds[kNaClParentFDIndex(child_fds.size())], buffer,
+           kMaxReadSize));
   const std::string switch_prefix = std::string("--") +
       switches::kProcessChannelID + std::string("=");
   const size_t len = switch_prefix.length();
@@ -95,9 +96,9 @@ void ChildNaClLoaderInit(const std::vector<int>& child_fds,
       validack = true;
     }
   }
-  if (HANDLE_EINTR(close(child_fds[kNaClDummyFDIndex])) != 0)
+  if (HANDLE_EINTR(close(child_fds[kNaClDummyFDIndex(child_fds.size())])) != 0)
     LOG(ERROR) << "close(child_fds[kNaClDummyFDIndex]) failed";
-  if (HANDLE_EINTR(close(child_fds[kNaClParentFDIndex])) != 0)
+  if (HANDLE_EINTR(close(child_fds[kNaClParentFDIndex(child_fds.size())])) != 0)
     LOG(ERROR) << "close(child_fds[kNaClParentFDIndex]) failed";
   if (validack) {
     BecomeNaClLoader(child_fds, system_info);
@@ -113,7 +114,7 @@ void ChildNaClLoaderInit(const std::vector<int>& child_fds,
 bool HandleForkRequest(const std::vector<int>& child_fds,
                        const NaClLoaderSystemInfo& system_info,
                        Pickle* output_pickle) {
-  if (kNaClParentFDIndex + 1 != child_fds.size()) {
+  if (kNaClParentFDIndex(child_fds.size()) + 1 != child_fds.size()) {
     LOG(ERROR) << "nacl_helper: unexpected number of fds, got "
         << child_fds.size();
     return false;