crypto: inline PrivateCrossSigningIdentity::with_account

This was now only used in one place, and I think it makes more sense to inline
it into olm::Account than leave it in `PrivateCrossSigningIdentity`.

crates/matrix-sdk-crypto/src/olm/account.rs

@@ -806,11 +806,30 @@ impl Account {
         device_keys
     }
 
-    /// Bootstrap Cross-Signing
+    /// Bootstraps cross-signing, generating new cross-signing keys and creating
+    /// the necessary upload and signature requests.
+    ///
+    /// # Returns
+    /// A tuple containing:
+    /// - [`PrivateCrossSigningIdentity`]: The newly-generated cross-signing
+    ///   identity (including a signature from this device).
+    /// - [`UploadSigningKeysRequest`]: The request to upload the
+    ///   newly-generated cross-signing keys to the server.
+    /// - [`SignatureUploadRequest`]: The request to upload the signature of
+    ///   this device to the server.
     pub async fn bootstrap_cross_signing(
         &self,
     ) -> (PrivateCrossSigningIdentity, UploadSigningKeysRequest, SignatureUploadRequest) {
-        PrivateCrossSigningIdentity::with_account(self).await
+        let identity = PrivateCrossSigningIdentity::for_account(self);
+
+        let signature_request = identity
+            .sign_account(self.static_data())
+            .await
+            .expect("Can't sign own device with new cross signing keys");
+
+        let upload_request = identity.as_upload_request().await;
+
+        (identity, upload_request, signature_request)
     }
 
     /// Sign the given CrossSigning Key in place

crates/matrix-sdk-crypto/src/olm/signing/mod.rs

@@ -499,31 +499,6 @@ impl PrivateCrossSigningIdentity {
             .sign(message))
     }
 
-    /// Create a new identity for the given Olm Account.
-    ///
-    /// Returns the new identity, the upload signing keys request and a
-    /// signature upload request that contains the signature of the account
-    /// signed by the self signing key.
-    ///
-    /// # Arguments
-    ///
-    /// * `account` - The Olm account that is creating the new identity. The
-    ///   account will sign the master key and the self signing key will sign
-    ///   the account.
-    pub(crate) async fn with_account(
-        account: &Account,
-    ) -> (Self, UploadSigningKeysRequest, SignatureUploadRequest) {
-        let identity = Self::for_account(account);
-        let signature_request = identity
-            .sign_account(account.static_data())
-            .await
-            .expect("Can't sign own device with new cross signing keys");
-
-        let request = identity.as_upload_request().await;
-
-        (identity, request, signature_request)
-    }
-
     fn new_helper(user_id: &UserId, master: MasterSigning) -> Self {
         let (user, self_signing) = master.new_subkeys();