Fix all failed and canceled URLRequestStatuses without errors.

net/url_request/url_request_status.cc

Index: net/url_request/url_request_status.cc
diff --git a/net/url_request/url_request_status.cc b/net/url_request/url_request_status.cc
index c4643f260b8605827df9661379cbdc2967261926..2a6a2fae861c202a51fc677558a7f3584c286373 100644
--- a/net/url_request/url_request_status.cc
+++ b/net/url_request/url_request_status.cc
@@ -4,10 +4,36 @@
 
 #include "net/url_request/url_request_status.h"
 
+#include "base/logging.h"
 #include "net/base/net_errors.h"
 
 namespace net {
 
+URLRequestStatus::URLRequestStatus(Status status, int error)
+    : status_(status), error_(error) {
+  // URLRequestStatus should get folded into error. However, it is possible to
+  // create URLRequestStatuses with inconsistent |status_| and |error_|
+  // fields. As callers are cleaned up, these assertions avoid regressing any
+  // invariants that have been established.
+  //
+  // https://crbug.com/490311
+  DCHECK_GE(0, error_);
+  switch (status_) {
+    case SUCCESS:
+      DCHECK_EQ(OK, error_);
+      break;
+    case IO_PENDING:
+      // TODO(davidben): Switch all IO_PENDING status to ERR_IO_PENDING.
+      DCHECK(error_ == 0 || error_ == ERR_IO_PENDING);
+      break;
+    case CANCELED:
+    case FAILED:
+      DCHECK_NE(OK, error_);
+      DCHECK_NE(ERR_IO_PENDING, error_);
+      break;
+  }
+}
+
 URLRequestStatus URLRequestStatus::FromError(int error) {
   if (error == OK) {
     return URLRequestStatus(SUCCESS, OK);