Small: Start checking URLs using PVer4. Verdict not returned to client yet.

components/safe_browsing_db/v4_local_database_manager.h

Index: components/safe_browsing_db/v4_local_database_manager.h
diff --git a/components/safe_browsing_db/v4_local_database_manager.h b/components/safe_browsing_db/v4_local_database_manager.h
index f9510c4af51fceb49f9b354f6f31c2ab34a57558..480feb17fcef6347f5547d7b2f27406313605baa 100644
--- a/components/safe_browsing_db/v4_local_database_manager.h
+++ b/components/safe_browsing_db/v4_local_database_manager.h
@@ -37,9 +37,9 @@ class V4LocalDatabaseManager : public SafeBrowsingDatabaseManager {
     CHECK_MAX
   };
 
-  // Construct V4LocalDatabaseManager.
-  // Must be initialized by calling StartOnIOThread() before using.
-  V4LocalDatabaseManager(const base::FilePath& base_path);
+  // Create and return an instance of V4LocalDatabaseManager, if Finch trial
+  // allows it; nullptr otherwise.
+  static V4LocalDatabaseManager* Create(const base::FilePath& base_path);

[Nathan Parker, 2016/09/28 22:25:55]

return a unique_ptr

[vakh (use Gerrit instead), 2016/09/28 23:00:02]

It looks like the destructor of the class needs to be public for creating a
unique_ptr but the destructor of V4LocalDatabaseManager can't be made public
according to Chromium style guide.

../../components/safe_browsing_db/v4_local_database_manager.cc:87:1: error:
[chromium-style] Classes that are ref-counted should have destructors that are
declared protected or private.
V4LocalDatabaseManager::~V4LocalDatabaseManager() {
^
../../components/safe_browsing_db/v4_local_database_manager.h:29:32: note:
[chromium-style] 'V4LocalDatabaseManager' inherits from
'safe_browsing::SafeBrowsingDatabaseManager' here
class V4LocalDatabaseManager : public SafeBrowsingDatabaseManager {
                               ^
../../components/safe_browsing_db/database_manager.h:36:7: note:
[chromium-style] 'SafeBrowsingDatabaseManager' inherits from
'base::RefCountedThreadSafe<SafeBrowsingDatabaseManager>' here
    : public base::RefCountedThreadSafe<SafeBrowsingDatabaseManager> {

[Nathan Parker, 2016/09/28 23:50:14]

Ah yes, it's a base::RefCountedThreadSafe<> decendent, so maybe it should return
a scoped_refptr<v4ldm> (via make_scoped_refptr(..)).  Or maybe it'd need to be a
scoped_refptr<sbdm>, which might be annoying for tests since you'd need to
upcast it.  

If none of that works, this is probably ok.

 
   //
   // SafeBrowsingDatabaseManager implementation
@@ -74,6 +74,10 @@ class V4LocalDatabaseManager : public SafeBrowsingDatabaseManager {
   //
 
  protected:
+  // Construct V4LocalDatabaseManager.
+  // Must be initialized by calling StartOnIOThread() before using.
+  V4LocalDatabaseManager(const base::FilePath& base_path);
+
   // The information we need to process a URL safety reputation request and
   // respond to the SafeBrowsing client that asked for it.
   // TODO(vakh): In its current form, it only includes information for