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 74c6e0f75e20290992d96cb1a221c4c4cae59e94..1b1440752a013c4a86b0489fbbf90aae33e02fd6 100644
--- a/content/browser/ppapi_plugin_process_host.cc
+++ b/content/browser/ppapi_plugin_process_host.cc
@@ -38,6 +38,7 @@
 #if defined(OS_WIN)
 #include "content/browser/renderer_host/dwrite_font_proxy_message_filter_win.h"
 #include "content/common/sandbox_win.h"
+#include "content/public/common/prefetch_argument_win.h"
 #include "sandbox/win/src/process_mitigations.h"
 #include "sandbox/win/src/sandbox_policy.h"
 #include "ui/gfx/win/dpi.h"
@@ -368,6 +369,11 @@ bool PpapiPluginProcessHost::Init(const PepperPluginInfo& info) {
                                          : switches::kPpapiPluginProcess);
   cmd_line->AppendSwitchASCII(switches::kProcessChannelID, channel_id);
 
+#if defined(OS_WIN)
+  AddWindowsPrefetchArgument(
+      is_broker_ ? PREFETCH_ID_DEFAULT : PREFETCH_ID_PPAPI, cmd_line);

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

What made you decide to have a special ID for one but not the other? Add a
comment explaining why?

+#endif  // defined(OS_WIN)
+
   // These switches are forwarded to both plugin and broker pocesses.
   static const char* kCommonForwardSwitches[] = {
     switches::kVModule