[webcrypto] Make operations run on worker threads.

content/child/webcrypto/status.h

Index: content/child/webcrypto/status.h
diff --git a/content/child/webcrypto/status.h b/content/child/webcrypto/status.h
index 46bdee1482f0bd9dbbf3dae44c01988a974fed40..3d67f6b17bb198838eb31115fa502a1bad8f992e 100644
--- a/content/child/webcrypto/status.h
+++ b/content/child/webcrypto/status.h
@@ -40,12 +40,14 @@ namespace webcrypto {
 // As such, it is important that errors DO NOT reveal any sensitive material
 // (like key bytes).
 //
-// Care must be taken with what errors are reported back to blink when doing
+// Care must be taken with what errors are reported back to Blink when doing
 // compound operations like unwrapping a JWK key. In this case, errors
 // generated by the JWK import are not appropriate to report since the wrapped
 // JWK is not visible to the caller.
 class CONTENT_EXPORT Status {
  public:
+  Status() : type_(TYPE_ERROR) {}
+
   // Returns true if the Status represents an error (any one of them).
   bool IsError() const;