[PM] Fix chrome://discards/graph view.

This was broken in https://crrev.com/c/2472484.

Bug: 1142423
Change-Id: Ia75b428c5e3aa0fccca0563d8cb071852faca0e7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2498861Reviewed-by: François Doray <fdoray@chromium.org>
Commit-Queue: Sigurður Ásgeirsson <siggi@chromium.org>
Auto-Submit: Sigurður Ásgeirsson <siggi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#820796}

chrome/browser/resources/discards/graph_doc.js

@@ -2,7 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import {FavIconInfo, FrameInfo, GraphChangeStreamInterface, PageInfo, ProcessInfo, WorkerInfo} from './chrome/browser/ui/webui/discards/discards.mojom-webui.js';
+// This file is loaded into a <webview> and cannot reference any chrome:
+// resources. The only communication to and from this implementation and the
+// WebUI is through postMessage.
 
 // Radius of a node circle.
 const /** number */ kNodeRadius = 6;