Use a valid /prefetch argument when launching a process.

chrome/browser/chrome_content_browser_client_unittest.cc

Index: chrome/browser/chrome_content_browser_client_unittest.cc
diff --git a/chrome/browser/chrome_content_browser_client_unittest.cc b/chrome/browser/chrome_content_browser_client_unittest.cc
index e4b60d6a085d64cbd62bff4ec8bf056e6f89e352..78c0d5a9a01797e8a1eda5cd25dc2e5ffb3767c9 100644
--- a/chrome/browser/chrome_content_browser_client_unittest.cc
+++ b/chrome/browser/chrome_content_browser_client_unittest.cc
@@ -167,6 +167,10 @@ class BlinkSettingsFieldTrialTest : public testing::Test {
   void SetUp() override {
     command_line_.AppendSwitchASCII(
         switches::kProcessType, switches::kRendererProcess);
+
+#if defined(OS_WIN)
+    command_line_.AppendArg(switches::kPrefetchArgumentRenderer);

[gab, 2016/01/26 21:40:26]

This is a unittest, I would guess it doesn't go through the DCHECK in main, no?
If so, I'd say don't put it here.

[fdoray, 2016/01/27 20:12:19]

Done.

+#endif  // defined(OS_WIN)
   }
 
   void TearDown() override {