Split FlowDelegate into DeviceFlowDelegate and InstalledFlowDelegate.

Each flow invokes a non-overlapping set of methods. There doesn't appear
to be any benefit in having both flows use a common trait. The benefit
of splitting the traits is that it makes it clear which methods need to
be updated for each flow type where previously comments were required to
communicate that information.

src/installed.rs

@@ -2,7 +2,7 @@
 //
 // Refer to the project root for licensing information.
 //
-use crate::authenticator_delegate::{DefaultFlowDelegate, FlowDelegate};
+use crate::authenticator_delegate::{DefaultInstalledFlowDelegate, InstalledFlowDelegate};
 use crate::error::{Error, JsonErrorOr};
 use crate::types::{ApplicationSecret, Token};
 
@@ -68,7 +68,7 @@ pub enum InstalledFlowReturnMethod {
 pub struct InstalledFlow {
     pub(crate) app_secret: ApplicationSecret,
     pub(crate) method: InstalledFlowReturnMethod,
-    pub(crate) flow_delegate: Box<dyn FlowDelegate>,
+    pub(crate) flow_delegate: Box<dyn InstalledFlowDelegate>,
 }
 
 impl InstalledFlow {
@@ -80,7 +80,7 @@ impl InstalledFlow {
         InstalledFlow {
             app_secret,
             method,
-            flow_delegate: Box::new(DefaultFlowDelegate),
+            flow_delegate: Box::new(DefaultInstalledFlowDelegate),
         }
     }
 
@@ -89,7 +89,7 @@ impl InstalledFlow {
     /// . Obtain a token and refresh token using that code.
     /// . Return that token
     ///
-    /// It's recommended not to use the DefaultFlowDelegate, but a specialized one.
+    /// It's recommended not to use the DefaultInstalledFlowDelegate, but a specialized one.
     pub(crate) async fn token<C, T>(
         &self,
         hyper_client: &hyper::Client<C>,
@@ -404,7 +404,7 @@ mod tests {
     use mockito::mock;
 
     use super::*;
-    use crate::authenticator_delegate::FlowDelegate;
+    use crate::authenticator_delegate::InstalledFlowDelegate;
 
     #[tokio::test]
     async fn test_end2end() {
@@ -413,7 +413,7 @@ mod tests {
             String,
             hyper::Client<HttpsConnector<HttpConnector>, hyper::Body>,
         );
-        impl FlowDelegate for FD {
+        impl InstalledFlowDelegate for FD {
             /// Depending on need_code, return the pre-set code or send the code to the server at
             /// the redirect_uri given in the url.
             fn present_user_url<'a>(