Implement main CertificateReportingService code and add unit tests.

chrome/browser/ssl/certificate_reporting_test_utils.cc

Index: chrome/browser/ssl/certificate_reporting_test_utils.cc
diff --git a/chrome/browser/ssl/certificate_reporting_test_utils.cc b/chrome/browser/ssl/certificate_reporting_test_utils.cc
index eb6249c26f19ad7c449be7b17fb6c983f9e4edc4..5089a06c26d3f6a4ac6de31523766733f9d5f9bf 100644
--- a/chrome/browser/ssl/certificate_reporting_test_utils.cc
+++ b/chrome/browser/ssl/certificate_reporting_test_utils.cc
@@ -67,6 +67,9 @@ class MockSSLCertReporter : public SSLCertReporter {
     }
   }
 
+  // SSLCertReporter implementation.
+  void OnDidNotSendReport() override {}
+
   void set_expect_report(bool expect_report) { expect_report_ = expect_report; }
 
  private: