Only show Reader Mode infobar on long articles

components/dom_distiller/content/renderer/distillability_agent.cc

Index: components/dom_distiller/content/renderer/distillability_agent.cc
diff --git a/components/dom_distiller/content/renderer/distillability_agent.cc b/components/dom_distiller/content/renderer/distillability_agent.cc
index 99592ef0b6fef51c3ca712a6de556bd29d3c8e33..8c01a6ed2b928a9cab08de1acae87298d3ee5efb 100644
--- a/components/dom_distiller/content/renderer/distillability_agent.cc
+++ b/components/dom_distiller/content/renderer/distillability_agent.cc
@@ -52,13 +52,14 @@ bool IsLast(bool is_loaded) {
 
 bool IsDistillablePageAdaboost(WebDocument& doc,
                                const DistillablePageDetector* detector,
+                               const DistillablePageDetector* long_page,

[mdjones, 2016/02/18 17:17:21]

If we add any more of these, we can probably just pass an array of page
detectors.

[wychen, 2016/02/18 21:47:23]

Acknowledged. It's hard to say whether we need more, or how
it would be used. If it's not ANDed together, having named
variable for each one is easier to understand.

                                bool is_last) {
   WebDistillabilityFeatures features = doc.distillabilityFeatures();
   GURL parsed_url(doc.url());
   if (!parsed_url.is_valid()) {
     return false;
   }
-  bool distillable = detector->Classify(CalculateDerivedFeatures(
+  std::vector<double> derived = CalculateDerivedFeatures(
     features.openGraph,
     parsed_url,
     features.elementCount,
@@ -67,7 +68,9 @@ bool IsDistillablePageAdaboost(WebDocument& doc,
     features.mozScore,
     features.mozScoreAllSqrt,
     features.mozScoreAllLinear
-  ));
+  );
+  bool distillable = detector->Classify(derived);
+  bool long_article = long_page->Classify(derived);
 
   int bucket = static_cast<unsigned>(features.isMobileFriendly) |
       (static_cast<unsigned>(distillable) << 1);
@@ -78,7 +81,7 @@ bool IsDistillablePageAdaboost(WebDocument& doc,
     UMA_HISTOGRAM_ENUMERATION("DomDistiller.PageDistillableAfterParsing",
         bucket, 4);
   }
-  return distillable && (!features.isMobileFriendly);
+  return distillable && long_article && (!features.isMobileFriendly);
 }
 
 bool IsDistillablePage(WebDocument& doc, bool is_last) {
@@ -88,8 +91,9 @@ bool IsDistillablePage(WebDocument& doc, bool is_last) {
     case DistillerHeuristicsType::OG_ARTICLE:
       return doc.distillabilityFeatures().openGraph;
     case DistillerHeuristicsType::ADABOOST_MODEL:
-      return IsDistillablePageAdaboost(
-          doc, DistillablePageDetector::GetNewModel(), is_last);
+      return IsDistillablePageAdaboost(doc,
+          DistillablePageDetector::GetNewModel(),
+          DistillablePageDetector::GetLongPageModel(), is_last);
     case DistillerHeuristicsType::NONE:
     default:
       return false;