Add a PrefetchList to Prerender Local Predictor, to emulate how effective

chrome/browser/prerender/prerender_field_trial.cc

Index: chrome/browser/prerender/prerender_field_trial.cc
diff --git a/chrome/browser/prerender/prerender_field_trial.cc b/chrome/browser/prerender/prerender_field_trial.cc
index bb1d567bda67ab33d175c4cf46739f391711a80b..d89a31d77d3bf6a3f1651f67b7c298ec8eca226e 100644
--- a/chrome/browser/prerender/prerender_field_trial.cc
+++ b/chrome/browser/prerender/prerender_field_trial.cc
@@ -54,6 +54,7 @@ const char kPrerenderQueryPrerenderServiceCandidateURLsKeyName[] =
 const char kPrerenderServiceBehaviorIDKeyName[] = "PrerenderServiceBehaviorID";
 const char kPrerenderServiceFetchTimeoutKeyName[] =
     "PrerenderServiceFetchTimeoutMs";
+const char kPrefetchListTimeoutKeyName[] = "PrefetchListTimeoutSeconds";
 const char kPrerenderTTLKeyName[] = "PrerenderTTLSeconds";
 const char kPrerenderPriorityHalfLifeTimeKeyName[] =
     "PrerenderPriorityHalfLifeTimeSeconds";
@@ -72,6 +73,9 @@ const char kDefaultPrerenderServiceURLPrefix[] =
 const int kMinPrerenderServiceTimeoutMs = 1;
 const int kMaxPrerenderServiceTimeoutMs = 10000;
 const int kDefaultPrerenderServiceTimeoutMs = 1000;
+const int kMinPrefetchListTimeoutSeconds = 1;
+const int kMaxPrefetchListTimeoutSeconds = 1800;
+const int kDefaultPrefetchListTimeoutSeconds = 300;
 const char kSkipPrerenderLocalCanadidates[] = "SkipPrerenderLocalCandidates";
 const char kSkipPrerenderServiceCanadidates[] =
     "SkipPrerenderServiceCandidates";
@@ -382,6 +386,15 @@ int GetPrerenderServiceFetchTimeoutMs() {
       kDefaultPrerenderServiceTimeoutMs : result;
 }
 
+int GetPrerenderPrefetchListTimeoutSeconds() {
+  int result;
+  StringToInt(GetLocalPredictorSpecValue(kPrefetchListTimeoutKeyName), &result);

[davidben, 2014/08/05 18:51:12]

Nit: Check for StringToInt returning false here, so we're not reading an
uninitialized value if that fails.

[tburkard, 2014/08/05 20:05:54]

See comment in base/strings/string_number_conversions.h
StringToInt will always set result to something, the return value only indicates
if it was a "perfect" conversion or not.

So result will always have a defined value, and the check afterwards will ensure
it is in the correct range.

+  // If the value is outside the valid range, use the default value.
+  return (result < kMinPrefetchListTimeoutSeconds ||
+          result > kMaxPrefetchListTimeoutSeconds) ?
+      kDefaultPrefetchListTimeoutSeconds : result;
+}
+
 int GetLocalPredictorTTLSeconds() {
   int ttl;
   StringToInt(GetLocalPredictorSpecValue(kPrerenderTTLKeyName), &ttl);