Fix ignored |ukm_params| ctor parameter in CanvasAsyncBlobCreator.

Bug: 1138586
Change-Id: Ie3f67b8db60c66c1920b9af8e3c1ec03edc4921f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2472264
Auto-Submit: Chris Fredrickson <cfredric@google.com>
Commit-Queue: Fernando Serboncini <fserb@chromium.org>
Reviewed-by: Fernando Serboncini <fserb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#817480}

third_party/blink/renderer/core/html/canvas/canvas_async_blob_creator.cc

@@ -179,6 +179,7 @@ CanvasAsyncBlobCreator::CanvasAsyncBlobCreator(
       start_time_(start_time),
       static_bitmap_image_loaded_(false),
       callback_(callback),
+      ukm_params_(ukm_params),
       script_promise_resolver_(resolver) {
   DCHECK(image);
   DCHECK(context);