Browser tests for using the new SafeBrowsing protocol (v4)

chrome/browser/safe_browsing/safe_browsing_service.h

Index: chrome/browser/safe_browsing/safe_browsing_service.h
diff --git a/chrome/browser/safe_browsing/safe_browsing_service.h b/chrome/browser/safe_browsing/safe_browsing_service.h
index d1d355499100f56654c773e772e1a2d32068da10..e201aec73bc6a742f841050f04c88b04bb974644 100644
--- a/chrome/browser/safe_browsing/safe_browsing_service.h
+++ b/chrome/browser/safe_browsing/safe_browsing_service.h
@@ -197,7 +197,8 @@ class SafeBrowsingService : public base::RefCountedThreadSafe<
 
  protected:
   // Creates the safe browsing service.  Need to initialize before using.
-  SafeBrowsingService();
+  explicit SafeBrowsingService(bool v4_enabled = false,
+                               bool use_v4_only = false);

[Scott Hess - ex-Googler, 2017/02/06 22:46:35]

This feels like a case where some well-chosen enum names would improve
readability.  Like V4_DISABLED, V4_ENABLED, and V4_ONLY or something like that.

[vakh (use Gerrit instead), 2017/02/06 23:30:12]

Done.

 
   ~SafeBrowsingService() override;
 
@@ -298,7 +299,12 @@ class SafeBrowsingService : public base::RefCountedThreadSafe<
 
   // Whether SafeBrowsing needs to be enabled in V4Only mode. In this mode, all
   // SafeBrowsing decisions are made using the PVer4 implementation.
-  bool enabled_v4_only_;
+  bool use_v4_only_;
+
+  // Whether the PVer4 implementation needs to be instantiated. Note that even
+  // if the PVer4 implementation has been instantiated, it is used only if
+  // |use_v4_only_| is true.
+  bool v4_enabled_;
 
   // Tracks existing PrefServices, and the safe browsing preference on each.
   // This is used to determine if any profile is currently using the safe