DOMException toString is not correct

LayoutTests/http/tests/security/canvas-remote-read-remote-image-redirect-expected.txt

Index: LayoutTests/http/tests/security/canvas-remote-read-remote-image-redirect-expected.txt
diff --git a/LayoutTests/http/tests/security/canvas-remote-read-remote-image-redirect-expected.txt b/LayoutTests/http/tests/security/canvas-remote-read-remote-image-redirect-expected.txt
index 0358abcd5ff8c36831cfa975b47832c6c665f76e..1136d84f94300d6581e385bfdfa510b9869b402e 100644
--- a/LayoutTests/http/tests/security/canvas-remote-read-remote-image-redirect-expected.txt
+++ b/LayoutTests/http/tests/security/canvas-remote-read-remote-image-redirect-expected.txt
@@ -8,12 +8,12 @@ PASS: Calling toDataURL() on an untainted canvas was allowed.
 
 
 Tainted canvas:
-PASS: Calling getImageData() from a canvas tainted by a remote image was not allowed - Threw error: Error: SecurityError: DOM Exception 18.
-PASS: Calling toDataURL() on a canvas tainted by a remote image was not allowed - Threw error: Error: SecurityError: DOM Exception 18.
-PASS: Calling getImageData() from a canvas tainted by a tainted canvas was not allowed - Threw error: Error: SecurityError: DOM Exception 18.
-PASS: Calling toDataURL() on a canvas tainted by a tainted canvas was not allowed - Threw error: Error: SecurityError: DOM Exception 18.
-PASS: Calling getImageData() from a canvas tainted by a remote image tainted pattern was not allowed - Threw error: Error: SecurityError: DOM Exception 18.
-PASS: Calling toDataURL() on a canvas tainted by a remote image tainted pattern was not allowed - Threw error: Error: SecurityError: DOM Exception 18.
-PASS: Calling getImageData() from a canvas tainted by a tainted canvas pattern was not allowed - Threw error: Error: SecurityError: DOM Exception 18.
-PASS: Calling toDataURL() on a canvas tainted by a tainted canvas pattern was not allowed - Threw error: Error: SecurityError: DOM Exception 18.
+PASS: Calling getImageData() from a canvas tainted by a remote image was not allowed - Threw error: SecurityError: An attempt was made to break through the security policy of the user agent..
+PASS: Calling toDataURL() on a canvas tainted by a remote image was not allowed - Threw error: SecurityError: An attempt was made to break through the security policy of the user agent..
+PASS: Calling getImageData() from a canvas tainted by a tainted canvas was not allowed - Threw error: SecurityError: An attempt was made to break through the security policy of the user agent..
+PASS: Calling toDataURL() on a canvas tainted by a tainted canvas was not allowed - Threw error: SecurityError: An attempt was made to break through the security policy of the user agent..
+PASS: Calling getImageData() from a canvas tainted by a remote image tainted pattern was not allowed - Threw error: SecurityError: An attempt was made to break through the security policy of the user agent..
+PASS: Calling toDataURL() on a canvas tainted by a remote image tainted pattern was not allowed - Threw error: SecurityError: An attempt was made to break through the security policy of the user agent..
+PASS: Calling getImageData() from a canvas tainted by a tainted canvas pattern was not allowed - Threw error: SecurityError: An attempt was made to break through the security policy of the user agent..
+PASS: Calling toDataURL() on a canvas tainted by a tainted canvas pattern was not allowed - Threw error: SecurityError: An attempt was made to break through the security policy of the user agent..