Use a valid /prefetch argument when launching a process.

content/browser/plugin_process_host.cc

Index: content/browser/plugin_process_host.cc
diff --git a/content/browser/plugin_process_host.cc b/content/browser/plugin_process_host.cc
index 9ede7a2cf42dde9c0f82f3b92bf9af473717a94f..273cb09ac07bf77584ec204fff9774827eabbace 100644
--- a/content/browser/plugin_process_host.cc
+++ b/content/browser/plugin_process_host.cc
@@ -47,6 +47,7 @@
 
 #if defined(OS_WIN)
 #include <windows.h>
+#include "content/public/common/prefetch_argument_win.h"
 #endif
 
 #if defined(OS_MACOSX)
@@ -209,6 +210,10 @@ bool PluginProcessHost::Init(const WebPluginInfo& info) {
   cmd_line->AppendSwitchASCII(switches::kProcessType, switches::kPluginProcess);
   cmd_line->AppendSwitchPath(switches::kPluginPath, info.path);
 
+#if defined(OS_WIN)
+  AddWindowsPrefetchArgument(PREFETCH_ID_DEFAULT, cmd_line);

[gab, 2016/01/21 20:22:59]

How about "PREFETCH_ID_OTHER" (i.e. to me "default" is the browser process'
while "other" is clear it's for things we don't care much about).

+#endif  // defined(OS_WIN)
+
   // Propagate the following switches to the plugin command line (along with
   // any associated values) if present in the browser command line
   static const char* const kSwitchNames[] = {