Use a valid /prefetch argument when launching a process.

content/browser/ppapi_plugin_process_host.cc

Index: content/browser/ppapi_plugin_process_host.cc
diff --git a/content/browser/ppapi_plugin_process_host.cc b/content/browser/ppapi_plugin_process_host.cc
index 139cdeabafd5ad3be3ff782efcc0c2b482a3098d..56ae0eea7f4a8c901e0a6f080d06aa1fe49e62e6 100644
--- a/content/browser/ppapi_plugin_process_host.cc
+++ b/content/browser/ppapi_plugin_process_host.cc
@@ -394,6 +394,13 @@ bool PpapiPluginProcessHost::Init(const PepperPluginInfo& info) {
                                          : switches::kPpapiPluginProcess);
   cmd_line->AppendSwitchASCII(switches::kProcessChannelID, channel_id);
 
+#if defined(OS_WIN)
+  if (GetContentClient()->browser()->ShouldUseWindowsPrefetchArgument()) {
+    cmd_line->AppendArg(is_broker_ ? switches::kPrefetchArgumentPpapiBroker
+                                   : switches::kPrefetchArgumentPpapi);
+  }
+#endif  // defined(OS_WIN)
+
   // These switches are forwarded to both plugin and broker pocesses.
   static const char* kCommonForwardSwitches[] = {
     switches::kVModule