Update ActivityLog detection to use previous values, hrefs.

chrome/browser/extensions/activity_log/activity_actions.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_ACTIVITY_ACTIONS_H_
 #define CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_ACTIVITY_ACTIONS_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 29 matching lines @@
     UNUSED_ACTION_API_BLOCKED = 2,  // Not in use, but reserved for future.
     ACTION_CONTENT_SCRIPT = 3,
     ACTION_DOM_ACCESS = 4,
     ACTION_DOM_EVENT = 5,
     ACTION_WEB_REQUEST = 6,
     ACTION_ANY = 1001,              // Used for lookups of unspecified type.
   };
 
   // The type of ad injection an action performed.
   enum InjectionType {
-    NO_AD_INJECTION = 0,    // No ad injection occurred.
-    INJECTION_NEW_AD,       // A new ad was injected.
-    INJECTION_REMOVED_AD,   // An ad was removed.
-    INJECTION_REPLACED_AD,  // An ad was replaced.
-    NUM_INJECTION_TYPES     // Place any new injection types above this entry.
+    // No ad injection occurred.
+    NO_AD_INJECTION = 0,
+    // A new ad was injected.
+    INJECTION_NEW_AD,
+    // An ad was removed.
+    INJECTION_REMOVED_AD,
+    // An ad was replaced.
+    INJECTION_REPLACED_AD,
+    // Something occurred which heuristically looks like an ad injection, but we
+    // didn't categorize it as such (likely because we didn't recognize it as
+    // an ad network). If our list is effective, this should be significantly
+    // lower than the non-LIKELY counterparts.
+    INJECTION_LIKELY_NEW_AD,
+    INJECTION_LIKELY_REPLACED_AD,
+
+    // Place any new injection types above this entry.
+    NUM_INJECTION_TYPES
   };
 
   // A useful shorthand for methods that take or return collections of Action
   // objects.
   typedef std::vector<scoped_refptr<Action> > ActionVector;
 
   // Creates a new activity log Action object.  The extension_id and type
   // fields are immutable.  All other fields can be filled in with the
   // accessors/mutators below.
   Action(const std::string& extension_id,
@@ skipping 128 matching lines @@
 // comparisons.
 struct ActionComparatorExcludingTimeAndActionId {
   // Evaluates the comparison lhs < rhs.
   bool operator()(const scoped_refptr<Action>& lhs,
                   const scoped_refptr<Action>& rhs) const;
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_ACTIVITY_ACTIONS_H_