MacOS: Disable JIT entitlement for non-Flash plugin processes.

BUG=961831

Change-Id: Iaf98c71732e029d68cc6e97d5f9911676a154bd5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2079649Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Nasko Oskov <nasko@chromium.org>
Commit-Queue: Will Harris <wfh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#746883}

content/browser/ppapi_plugin_process_host.cc

@@ -369,7 +369,10 @@ bool PpapiPluginProcessHost::Init(const PepperPluginInfo& info) {
   int flags = plugin_launcher.empty() ? ChildProcessHost::CHILD_ALLOW_SELF :
                                         ChildProcessHost::CHILD_NORMAL;
 #elif defined(OS_MACOSX)
-  int flags = ChildProcessHost::CHILD_PLUGIN;
+  // Flash needs to JIT, but other plugins do not.
+  int flags = permissions_.HasPermission(ppapi::PERMISSION_FLASH)
+                  ? ChildProcessHost::CHILD_PLUGIN
+                  : ChildProcessHost::CHILD_NORMAL;
 #else
   int flags = ChildProcessHost::CHILD_NORMAL;
 #endif