predictors: Add a origin for prefetch requests, remove the URL/host settings.

chrome/browser/predictors/resource_prefetch_common.h

Index: chrome/browser/predictors/resource_prefetch_common.h
diff --git a/chrome/browser/predictors/resource_prefetch_common.h b/chrome/browser/predictors/resource_prefetch_common.h
index cfb422ce1fb715c8bb9c42e486e3043914e94d31..7dd2139bbb25e2b54d3b805954d8f6d416bccb6c 100644
--- a/chrome/browser/predictors/resource_prefetch_common.h
+++ b/chrome/browser/predictors/resource_prefetch_common.h
@@ -32,6 +32,9 @@ enum PrefetchKeyType {
   PREFETCH_KEY_TYPE_URL
 };
 
+// Indicates what caused the prefetch request.
+enum class PrefetchOrigin { NAVIGATION, EXTERNAL };
+
 // Represents a single navigation for a render frame.
 struct NavigationID {
   NavigationID();
@@ -59,8 +62,7 @@ struct NavigationID {
   base::TimeTicks creation_time;
 };
 
-// Represents the config for the resource prefetch prediction algorithm. It is
-// useful for running experiments.
+// Represents the config for the resource prefetch prediction algorithm.
 struct ResourcePrefetchPredictorConfig {
   // Initializes the config with default values.
   ResourcePrefetchPredictorConfig();
@@ -69,20 +71,17 @@ struct ResourcePrefetchPredictorConfig {
 
   // The mode the prefetcher is running in. Forms a bit map.
   enum Mode {
-    URL_LEARNING = 1 << 0,
-    HOST_LEARNING = 1 << 1,
-    URL_PREFETCHING = 1 << 2,  // Should also turn on URL_LEARNING.
-    HOST_PREFETCHING = 1 << 3  // Should also turn on HOST_LEARNING.
+    LEARNING = 1 << 0,
+    PREFETCHING_FOR_NAVIGATION = 1 << 2,  // Also enables LEARNING.
+    PREFETCHING_FOR_EXTERNAL = 1 << 3     // Also enables LEARNING.
   };
   int mode;
 
   // Helpers to deal with mode.
   bool IsLearningEnabled() const;
-  bool IsPrefetchingEnabled(Profile* profile) const;
-  bool IsURLLearningEnabled() const;
-  bool IsHostLearningEnabled() const;
-  bool IsURLPrefetchingEnabled(Profile* profile) const;
-  bool IsHostPrefetchingEnabled(Profile* profile) const;
+  bool IsPrefetchingEnabledForSomeOrigin(Profile* profile) const;
+  bool IsPrefetchingEnabledForOrigin(Profile* profile,
+                                     PrefetchOrigin origin) const;
 
   bool IsLowConfidenceForTest() const;
   bool IsHighConfidenceForTest() const;