Refactor ChromeFraudulentCertReporter for code reuse by SSL reporting

chrome/browser/net/cert_logger.proto

Index: chrome/browser/net/cert_logger.proto
diff --git a/chrome/browser/net/cert_logger.proto b/chrome/browser/net/cert_logger.proto
index be95005b70d2defe857551e8b7c2c95456ea0124..b42c5df7d5054c04d59d569322ddb5eacc0295b3 100644
--- a/chrome/browser/net/cert_logger.proto
+++ b/chrome/browser/net/cert_logger.proto
@@ -3,11 +3,12 @@
 // found in the LICENSE file.
 //
 // This protobuffer is intended to store reports from Chrome users of
-// certificate pinning errors. A report will be sent from Chrome when it gets
+// certificate errors. A report will be sent from Chrome when it gets
 // e.g. a certificate for google.com that chains up to a root CA not expected by
 // Chrome for that origin, such as DigiNotar (compromised in July 2011), or
-// other pinning errors such as a blacklisted cert in the chain. The
-// report from the user will include the hostname being accessed, 
+// other pinning errors such as a blacklisted cert in the chain, or
+// (when opted in) other certificate validation errors like an expired
+// cert. The report from the user will include the hostname being accessed,
 // the full certificate chain (in PEM format), and the
 // timestamp of when the client tried to access the site. A response is
 // generated by the frontend and logged, including validation and error checking