Add chrome channel to cert logger reports

components/certificate_reporting/cert_logger.proto

Index: components/certificate_reporting/cert_logger.proto
diff --git a/components/certificate_reporting/cert_logger.proto b/components/certificate_reporting/cert_logger.proto
index 0d4b7601ca1d0c76b3aa146c99ddba632e2373eb..a928b00f0afb8674795b0594e13d321fe18688d6 100644
--- a/components/certificate_reporting/cert_logger.proto
+++ b/components/certificate_reporting/cert_logger.proto
@@ -148,4 +148,16 @@ message CertLoggerRequest {
   // False when the report is attempted to be uploaded for the first time. True
   // in all other uploads.
   optional bool is_retry_upload = 11;
+
+  enum ChromeChannel {
+    NONE = 0;
+    UNKNOWN = 1;
+    DEV = 2;
+    CANARY = 3;
+    BETA = 4;
+    STABLE = 5;
+  };
+
+  // The Chrome channel that this error occurred on.
+  optional ChromeChannel chrome_channel = 12;
 };