Use constexpr TaskTraits constructor in chrome.

chrome/browser/android/thumbnail/thumbnail_cache.cc

Index: chrome/browser/android/thumbnail/thumbnail_cache.cc
diff --git a/chrome/browser/android/thumbnail/thumbnail_cache.cc b/chrome/browser/android/thumbnail/thumbnail_cache.cc
index 5653b6e32d9aa149af71762ccdf8215fa4b31caa..354da956350243a2f2d4bc9cede9c2346a211773 100644
--- a/chrome/browser/android/thumbnail/thumbnail_cache.cc
+++ b/chrome/browser/android/thumbnail/thumbnail_cache.cc
@@ -387,13 +387,11 @@ void ThumbnailCache::CompressThumbnailIfNecessary(
   gfx::Size encoded_size = GetEncodedSize(
       raw_data_size, ui_resource_provider_->SupportsETC1NonPowerOfTwo());
 
-  base::PostTaskWithTraits(
-      FROM_HERE, base::TaskTraits()
-                     .WithPriority(base::TaskPriority::BACKGROUND)
-                     .WithShutdownBehavior(
-                         base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN),
-      base::Bind(&ThumbnailCache::CompressionTask, bitmap, encoded_size,
-                 post_compression_task));
+  base::PostTaskWithTraits(FROM_HERE,
+                           {base::TaskPriority::BACKGROUND,
+                            base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN},
+                           base::Bind(&ThumbnailCache::CompressionTask, bitmap,
+                                      encoded_size, post_compression_task));
 }
 
 void ThumbnailCache::ReadNextThumbnail() {
@@ -774,8 +772,7 @@ void ThumbnailCache::ReadTask(
 
   if (decompress) {
     base::PostTaskWithTraits(
-        FROM_HERE,
-        base::TaskTraits().WithPriority(base::TaskPriority::BACKGROUND),
+        FROM_HERE, {base::TaskPriority::BACKGROUND},
         base::Bind(post_read_task, std::move(compressed_data), scale,
                    content_size));
   } else {