tools: Local tests for the speculative prefetch predictor.

chrome/common/chrome_switches.cc

Index: chrome/common/chrome_switches.cc
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index 6d8a898fdc971bf7be056cb377e93bb0c9e7c5c2..e6986563547c3fc9bce4ab89d5a0f3b9d1d44000 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -898,6 +898,9 @@ const char kSpeculativeResourcePrefetchingDisabled[] = "disabled";
 // Speculative resource prefetching is enabled.
 const char kSpeculativeResourcePrefetchingEnabled[] = "enabled";
 
+// Speculative resource prefetching is enabled for external requests.
+const char kSpeculativeResourceExternalPrefetchingEnabled[] = "external";
+
 // Speculative resource prefetching will only learn about resources that need to
 // be prefetched but will not prefetch them.
 const char kSpeculativeResourcePrefetchingLearning[] = "learning";