[stack_trace] Add StackTraceModel

We want one fragment trie per target, so we add a simple
StackTraceModel. This automatically takes care of the life-time for us.

The current plan is for StackTraceModel to be the "trie boundary". That
is callers should not be aware that fragments are stored in a trie.

[email protected]

Bug: 433162438
Change-Id: I3fbaddce5264855f740c88011d284bba53844b44
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6854804
Reviewed-by: Philip Pfaffe <[email protected]>
Commit-Queue: Simon Zünd <[email protected]>

Author: szuend

config/gni/devtools_grd_files.gni

@@ -1123,6 +1123,7 @@ grd_files_unbundled_sources = [
   "front_end/models/source_map_scopes/ScopeTreeCache.js",
   "front_end/models/stack_trace/StackTrace.js",
   "front_end/models/stack_trace/StackTraceImpl.js",
+  "front_end/models/stack_trace/StackTraceModel.js",
   "front_end/models/stack_trace/Trie.js",
   "front_end/models/text_utils/CodeMirrorUtils.js",
   "front_end/models/text_utils/ContentData.js",

front_end/models/stack_trace/BUILD.gn

@@ -27,11 +27,13 @@ devtools_entrypoint("bundle") {
 devtools_module("stack_trace_impl") {
   sources = [
     "StackTraceImpl.ts",
+    "StackTraceModel.ts",
     "Trie.ts",
   ]
 
   deps = [
     ":bundle",
+    "../../core/sdk:bundle",
     "../../generated",
   ]
 }

front_end/models/stack_trace/StackTraceModel.ts

@@ -0,0 +1,23 @@
+// 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.
+
+import * as SDK from '../../core/sdk/sdk.js';
+
+import {FragmentImpl} from './StackTraceImpl.js';
+import {type RawFrame, Trie} from './Trie.js';
+
+/**
+ * The {@link StackTraceModel} is a thin wrapper around a fragment trie.
+ *
+ * We want to store stack trace fragments per target so a SDKModel is the natural choice.
+ */
+export class StackTraceModel extends SDK.SDKModel.SDKModel<unknown> {
+  readonly #trie = new Trie();
+
+  createFragment(frames: RawFrame[]): FragmentImpl {
+    return FragmentImpl.getOrCreate(this.#trie.insert(frames));
+  }
+}
+
+SDK.SDKModel.SDKModel.register(StackTraceModel, {capabilities: SDK.Target.Capability.NONE, autostart: false});