Remove nonsfi token workaround.

components/nacl/browser/nacl_file_host.cc

Index: components/nacl/browser/nacl_file_host.cc
diff --git a/components/nacl/browser/nacl_file_host.cc b/components/nacl/browser/nacl_file_host.cc
index 17e5bc5ea4208b7df545403d7b6110361051c842..24873b0232b412a8e77316a8ab5cf7ccc5fcfd3a 100644
--- a/components/nacl/browser/nacl_file_host.cc
+++ b/components/nacl/browser/nacl_file_host.cc
@@ -122,6 +122,7 @@ void DoOpenPnaclFile(
 void DoOpenNaClExecutableOnThreadPool(
     scoped_refptr<nacl::NaClHostMessageFilter> nacl_host_message_filter,
     const GURL& file_url,
+    bool register_executable,

[Mark Seaborn, 2015/01/12 21:59:35]

How about calling this something like "enable_validation_caching"?

Understanding "register_executable" requires knowing more context of how this
part of validation caching works.

[teravest, 2015/01/13 16:47:34]

Done.

     IPC::Message* reply_msg) {
   DCHECK(BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());
 
@@ -138,16 +139,26 @@ void DoOpenNaClExecutableOnThreadPool(
   base::File file = nacl::OpenNaClReadExecImpl(file_path,
                                                true /* is_executable */);
   if (file.IsValid()) {
-    // This function is running on the blocking pool, but the path needs to be
-    // registered in a structure owned by the IO thread.
-    BrowserThread::PostTask(
-        BrowserThread::IO, FROM_HERE,
-        base::Bind(
-            &DoRegisterOpenedNaClExecutableFile,
-            nacl_host_message_filter,
-            Passed(file.Pass()), file_path, reply_msg,
-            static_cast<WriteFileInfoReply>(
-                NaClHostMsg_OpenNaClExecutable::WriteReplyParams)));
+    if (register_executable) {

[Mark Seaborn, 2015/01/12 21:59:34]

Can you add a comment to explain that: Both branches of this conditional will
behave correctly but have different performance trade-offs.  One registers the
FD for use with validation caching.  Registering the FD carries a small up-front
penalty but saves time later -- but that penalty isn't wanted in Non-SFI Mode
which doesn't need validation caching.

Without the explanation, this code is rather obscure. :-)

[teravest, 2015/01/13 16:47:34]

Good point. I've added a comment here.

+      // This function is running on the blocking pool, but the path needs to be
+      // registered in a structure owned by the IO thread.
+      BrowserThread::PostTask(
+          BrowserThread::IO, FROM_HERE,
+          base::Bind(
+              &DoRegisterOpenedNaClExecutableFile,
+              nacl_host_message_filter,
+              Passed(file.Pass()), file_path, reply_msg,
+              static_cast<WriteFileInfoReply>(
+                  NaClHostMsg_OpenNaClExecutable::WriteReplyParams)));
+    } else {
+      IPC::PlatformFileForTransit file_desc =
+          IPC::TakeFileHandleForProcess(file.Pass(),
+                                        nacl_host_message_filter->PeerHandle());
+      uint64_t dummy_file_token = 0;
+      NaClHostMsg_OpenNaClExecutable::WriteReplyParams(
+          reply_msg, file_desc, dummy_file_token, dummy_file_token);
+      nacl_host_message_filter->Send(reply_msg);
+    }
   } else {
     NotifyRendererOfError(nacl_host_message_filter.get(), reply_msg);
     return;
@@ -211,6 +222,7 @@ void OpenNaClExecutable(
     scoped_refptr<nacl::NaClHostMessageFilter> nacl_host_message_filter,
     int render_view_id,
     const GURL& file_url,
+    bool register_executable,
     IPC::Message* reply_msg) {
   if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
     BrowserThread::PostTask(
@@ -218,7 +230,10 @@ void OpenNaClExecutable(
         base::Bind(
             &OpenNaClExecutable,
             nacl_host_message_filter,
-            render_view_id, file_url, reply_msg));
+            render_view_id,
+            file_url,
+            register_executable,
+            reply_msg));
     return;
   }
 
@@ -247,7 +262,9 @@ void OpenNaClExecutable(
       base::Bind(
           &DoOpenNaClExecutableOnThreadPool,
           nacl_host_message_filter,
-          file_url, reply_msg))) {
+          file_url,
+          register_executable,
+          reply_msg))) {
     NotifyRendererOfError(nacl_host_message_filter.get(), reply_msg);
   }
 }