[protocol] Rename 'Connection' to 'ConnectionTransport'

This aligns nomenclature with puppeteer and frees up the name so we can
add a 'CDPConnection' class that operates on CDP messages rather then
raw strings.

[email protected]

Bug: 453469270
Change-Id: I1c5cf1f217d2f3cdef62f534b987fec5493aee91
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/7071006
Reviewed-by: Alex Rudenko <[email protected]>
Commit-Queue: Simon Zünd <[email protected]>

Author: szuend

config/gni/devtools_grd_files.gni

@@ -894,6 +894,7 @@ grd_files_unbundled_sources = [
   "front_end/core/platform/TypescriptUtilities.js",
   "front_end/core/platform/UIString.js",
   "front_end/core/platform/UserVisibleError.js",
+  "front_end/core/protocol_client/ConnectionTransport.js",
   "front_end/core/protocol_client/InspectorBackend.js",
   "front_end/core/protocol_client/NodeURL.js",
   "front_end/core/root/Runtime.js",

front_end/core/protocol_client/BUILD.gn

@@ -8,6 +8,7 @@ import("../../../scripts/build/typescript/typescript.gni")
 
 devtools_module("protocol_client") {
   sources = [
+    "ConnectionTransport.ts",
     "InspectorBackend.ts",
     "NodeURL.ts",
   ]

front_end/core/protocol_client/ConnectionTransport.ts

@@ -0,0 +1,26 @@
+// Copyright 2025 The Chromium Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+let connectionFactory: () => ConnectionTransport;
+
+export abstract class ConnectionTransport {
+  declare onMessage: ((arg0: Object) => void)|null;
+
+  // on message from browser
+  abstract setOnMessage(onMessage: (arg0: Object|string) => void): void;
+  abstract setOnDisconnect(onDisconnect: (arg0: string) => void): void;
+
+  // send raw CDP message to browser
+  abstract sendRawMessage(message: string): void;
+
+  abstract disconnect(): Promise<void>;
+
+  static setFactory(factory: () => ConnectionTransport): void {
+    connectionFactory = factory;
+  }
+
+  static getFactory(): () => ConnectionTransport {
+    return connectionFactory;
+  }
+}

front_end/core/protocol_client/InspectorBackend.ts

@@ -7,6 +7,7 @@ import type * as ProtocolProxyApi from '../../generated/protocol-proxy-api.js';
 import type * as Protocol from '../../generated/protocol.js';
 import type * as Platform from '../platform/platform.js';
 
+import {ConnectionTransport} from './ConnectionTransport.js';
 import {NodeURL} from './NodeURL.js';
 
 export const DevToolsStubErrorCode = -32015;
@@ -160,35 +161,6 @@ export class InspectorBackend {
   }
 }
 
-let connectionFactory: () => Connection;
-
-export class Connection {
-  declare onMessage: ((arg0: Object) => void)|null;
-
-  // on message from browser
-  setOnMessage(_onMessage: (arg0: Object|string) => void): void {
-  }
-
-  setOnDisconnect(_onDisconnect: (arg0: string) => void): void {
-  }
-
-  // send raw CDP message to browser
-  sendRawMessage(_message: string): void {
-  }
-
-  disconnect(): Promise<void> {
-    throw new Error('not implemented');
-  }
-
-  static setFactory(factory: () => Connection): void {
-    connectionFactory = factory;
-  }
-
-  static getFactory(): () => Connection {
-    return connectionFactory;
-  }
-}
-
 type SendRawMessageCallback = (...args: unknown[]) => void;
 
 export const test = {
@@ -232,18 +204,18 @@ export const test = {
 const LongPollingMethods = new Set<string>(['CSS.takeComputedStyleUpdates']);
 
 export class SessionRouter {
-  readonly #connection: Connection;
+  readonly #connection: ConnectionTransport;
   #lastMessageId = 1;
   #pendingResponsesCount = 0;
   readonly #pendingLongPollingMessageIds = new Set<number>();
   readonly #sessions = new Map<string, {
     target: TargetBase,
     callbacks: Map<number, CallbackWithDebugInfo>,
-    proxyConnection: Connection|undefined|null,
+    proxyConnection: ConnectionTransport|undefined|null,
   }>();
   #pendingScripts: Array<() => void> = [];
 
-  constructor(connection: Connection) {
+  constructor(connection: ConnectionTransport) {
     this.#connection = connection;
 
     test.deprecatedRunAfterPendingDispatches = this.deprecatedRunAfterPendingDispatches.bind(this);
@@ -259,7 +231,7 @@ export class SessionRouter {
     });
   }
 
-  registerSession(target: TargetBase, sessionId: string, proxyConnection?: Connection|null): void {
+  registerSession(target: TargetBase, sessionId: string, proxyConnection?: ConnectionTransport|null): void {
     // Only the Audits panel uses proxy connections. If it is ever possible to have multiple active at the
     // same time, it should be tested thoroughly.
     if (proxyConnection) {
@@ -297,7 +269,7 @@ export class SessionRouter {
     return this.#lastMessageId++;
   }
 
-  connection(): Connection {
+  connection(): ConnectionTransport {
     return this.#connection;
   }
 
@@ -497,7 +469,8 @@ export class TargetBase {
   #dispatchers: DispatcherMap = new Map();
 
   constructor(
-      needsNodeJSPatching: boolean, parentTarget: TargetBase|null, sessionId: string, connection: Connection|null) {
+      needsNodeJSPatching: boolean, parentTarget: TargetBase|null, sessionId: string,
+      connection: ConnectionTransport|null) {
     this.needsNodeJSPatching = needsNodeJSPatching;
     this.sessionId = sessionId;
 
@@ -511,7 +484,7 @@ export class TargetBase {
     } else if (connection) {
       router = new SessionRouter(connection);
     } else {
-      router = new SessionRouter(connectionFactory());
+      router = new SessionRouter(ConnectionTransport.getFactory()());
     }
 
     this.#router = router;

front_end/core/protocol_client/protocol_client.ts

@@ -2,10 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import * as ConnectionTransport from './ConnectionTransport.js';
 import * as InspectorBackend from './InspectorBackend.js';
 import * as NodeURL from './NodeURL.js';
 
 export {
+  ConnectionTransport,
   InspectorBackend,
   NodeURL,
 };

front_end/core/sdk/ChildTargetManager.ts

@@ -36,7 +36,7 @@ export class ChildTargetManager extends SDKModel<EventTypes> implements Protocol
   readonly #targetInfos = new Map<Protocol.Target.TargetID, Protocol.Target.TargetInfo>();
   readonly #childTargetsBySessionId = new Map<Protocol.Target.SessionID, Target>();
   readonly #childTargetsById = new Map<Protocol.Target.TargetID|'main', Target>();
-  readonly #parallelConnections = new Map<string, ProtocolClient.InspectorBackend.Connection>();
+  readonly #parallelConnections = new Map<string, ProtocolClient.ConnectionTransport.ConnectionTransport>();
   #parentTargetId: Protocol.Target.TargetID|null = null;
 
   constructor(parentTarget: Target) {
@@ -261,7 +261,7 @@ export class ChildTargetManager extends SDKModel<EventTypes> implements Protocol
   }
 
   async createParallelConnection(onMessage: (arg0: Object|string) => void):
-      Promise<{connection: ProtocolClient.InspectorBackend.Connection, sessionId: string}> {
+      Promise<{connection: ProtocolClient.ConnectionTransport.ConnectionTransport, sessionId: string}> {
     // The main Target id is actually just `main`, instead of the real targetId.
     // Get the real id (requires an async operation) so that it can be used synchronously later.
     const targetId = await this.getParentTargetId();
@@ -274,7 +274,7 @@ export class ChildTargetManager extends SDKModel<EventTypes> implements Protocol
 
   private async createParallelConnectionAndSessionForTarget(target: Target, targetId: Protocol.Target.TargetID):
       Promise<{
-        connection: ProtocolClient.InspectorBackend.Connection,
+        connection: ProtocolClient.ConnectionTransport.ConnectionTransport,
         sessionId: string,
       }> {
     const targetAgent = target.targetAgent();

front_end/core/sdk/Connections.ts

@@ -19,7 +19,7 @@ const UIStrings = {
 } as const;
 const str_ = i18n.i18n.registerUIStrings('core/sdk/Connections.ts', UIStrings);
 const i18nString = i18n.i18n.getLocalizedString.bind(undefined, str_);
-export class MainConnection implements ProtocolClient.InspectorBackend.Connection {
+export class MainConnection implements ProtocolClient.ConnectionTransport.ConnectionTransport {
   onMessage: ((arg0: Object|string) => void)|null = null;
   #onDisconnect: ((arg0: string) => void)|null = null;
   #messageBuffer = '';
@@ -81,7 +81,7 @@ export class MainConnection implements ProtocolClient.InspectorBackend.Connectio
   }
 }
 
-export class WebSocketConnection implements ProtocolClient.InspectorBackend.Connection {
+export class WebSocketConnection implements ProtocolClient.ConnectionTransport.ConnectionTransport {
   #socket: WebSocket|null;
   onMessage: ((arg0: Object|string) => void)|null = null;
   #onDisconnect: ((arg0: string) => void)|null = null;
@@ -176,7 +176,7 @@ export class WebSocketConnection implements ProtocolClient.InspectorBackend.Conn
   }
 }
 
-export class StubConnection implements ProtocolClient.InspectorBackend.Connection {
+export class StubConnection implements ProtocolClient.ConnectionTransport.ConnectionTransport {
   onMessage: ((arg0: Object|string) => void)|null = null;
   #onDisconnect: ((arg0: string) => void)|null = null;
 
@@ -213,17 +213,17 @@ export class StubConnection implements ProtocolClient.InspectorBackend.Connectio
   }
 }
 
-export interface ParallelConnectionInterface extends ProtocolClient.InspectorBackend.Connection {
+export interface ParallelConnectionInterface extends ProtocolClient.ConnectionTransport.ConnectionTransport {
   getSessionId: () => string;
   getOnDisconnect: () => ((arg0: string) => void) | null;
 }
 
 export class ParallelConnection implements ParallelConnectionInterface {
-  readonly #connection: ProtocolClient.InspectorBackend.Connection;
+  readonly #connection: ProtocolClient.ConnectionTransport.ConnectionTransport;
   #sessionId: string;
   onMessage: ((arg0: Object) => void)|null = null;
   #onDisconnect: ((arg0: string) => void)|null = null;
-  constructor(connection: ProtocolClient.InspectorBackend.Connection, sessionId: string) {
+  constructor(connection: ProtocolClient.ConnectionTransport.ConnectionTransport, sessionId: string) {
     this.#connection = connection;
     this.#sessionId = sessionId;
   }
@@ -265,13 +265,13 @@ export class ParallelConnection implements ParallelConnectionInterface {
 export async function initMainConnection(
     createRootTarget: () => Promise<void>,
     onConnectionLost: (message: Platform.UIString.LocalizedString) => void): Promise<void> {
-  ProtocolClient.InspectorBackend.Connection.setFactory(createMainConnection.bind(null, onConnectionLost));
+  ProtocolClient.ConnectionTransport.ConnectionTransport.setFactory(createMainConnection.bind(null, onConnectionLost));
   await createRootTarget();
   Host.InspectorFrontendHost.InspectorFrontendHostInstance.connectionReady();
 }
 
 function createMainConnection(onConnectionLost: (message: Platform.UIString.LocalizedString) => void):
-    ProtocolClient.InspectorBackend.Connection {
+    ProtocolClient.ConnectionTransport.ConnectionTransport {
   if (Root.Runtime.Runtime.isTraceApp()) {
     return new RehydratingConnection(onConnectionLost);
   }

front_end/core/sdk/RehydratingConnection.ts

@@ -63,7 +63,7 @@ export const enum RehydratingConnectionState {
   REHYDRATED = 3,
 }
 
-export class RehydratingConnection implements ProtocolClient.InspectorBackend.Connection {
+export class RehydratingConnection implements ProtocolClient.ConnectionTransport.ConnectionTransport {
   rehydratingConnectionState: RehydratingConnectionState = RehydratingConnectionState.UNINITIALIZED;
   onDisconnect: ((arg0: string) => void)|null = null;
   onMessage: ((arg0: Object) => void)|null = null;

front_end/core/sdk/Target.ts

@@ -39,7 +39,8 @@ export class Target extends ProtocolClient.InspectorBackend.TargetBase {
   constructor(
       targetManager: TargetManager, id: Protocol.Target.TargetID|'main', name: string, type: Type,
       parentTarget: Target|null, sessionId: string, suspended: boolean,
-      connection: ProtocolClient.InspectorBackend.Connection|null, targetInfo?: Protocol.Target.TargetInfo) {
+      connection: ProtocolClient.ConnectionTransport.ConnectionTransport|null,
+      targetInfo?: Protocol.Target.TargetInfo) {
     const needsNodeJSPatching = type === Type.NODE;
     super(needsNodeJSPatching, parentTarget, sessionId, connection);
     this.#targetManager = targetManager;

front_end/core/sdk/TargetManager.ts

@@ -209,7 +209,8 @@ export class TargetManager extends Common.ObjectWrapper.ObjectWrapper<EventTypes
 
   createTarget(
       id: Protocol.Target.TargetID|'main', name: string, type: TargetType, parentTarget: Target|null,
-      sessionId?: string, waitForDebuggerInPage?: boolean, connection?: ProtocolClient.InspectorBackend.Connection,
+      sessionId?: string, waitForDebuggerInPage?: boolean,
+      connection?: ProtocolClient.ConnectionTransport.ConnectionTransport,
       targetInfo?: Protocol.Target.TargetInfo): Target {
     const target = new Target(
         this, id, name, type, parentTarget, sessionId || '', this.#isSuspended, connection || null, targetInfo);