predictors: Refactor resource_prefetch_predictor triggering.

chrome/browser/predictors/resource_prefetcher_manager.h

Index: chrome/browser/predictors/resource_prefetcher_manager.h
diff --git a/chrome/browser/predictors/resource_prefetcher_manager.h b/chrome/browser/predictors/resource_prefetcher_manager.h
index 84a8ec528083f3c63df8936fb4e4090d45d51558..2212440ac4728e7389fe9f38720747b124e0cccb 100644
--- a/chrome/browser/predictors/resource_prefetcher_manager.h
+++ b/chrome/browser/predictors/resource_prefetcher_manager.h
@@ -47,8 +47,8 @@ class ResourcePrefetcherManager
 
   // Will create a new ResourcePrefetcher for a given main frame url if there
   // isn't one already for the same host.
-  void MaybeAddPrefetch(const GURL& main_frame_url,
-                        const std::vector<GURL>& urls);
+  virtual void MaybeAddPrefetch(const GURL& main_frame_url,

[alexilin, 2017/05/23 11:01:39]

"Virtual for testing" comment?

+                                const std::vector<GURL>& urls);
 
   // Stops the ResourcePrefetcher for a given main frame URL, if one was in
   // progress.
@@ -60,12 +60,13 @@ class ResourcePrefetcherManager
       std::unique_ptr<ResourcePrefetcher::PrefetcherStats> stats) override;
   net::URLRequestContext* GetURLRequestContext() override;
 
+ protected:
+  ~ResourcePrefetcherManager() override;
+
  private:
   friend class base::RefCountedThreadSafe<ResourcePrefetcherManager>;
   friend class MockResourcePrefetcherManager;
 
-  ~ResourcePrefetcherManager() override;
-
   ResourcePrefetchPredictor* predictor_;
   const LoadingPredictorConfig config_;
   net::URLRequestContextGetter* const context_getter_;