Mac Task Manager: fix label color for dark mode

Bug: 1018333
Change-Id: I0d185dfa8d39a3c07a9d275b64a4c2f00e4c2620
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1883873
Commit-Queue: Leonard Grey <lgrey@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709948}

chrome/browser/ui/cocoa/task_manager_mac.mm

@@ -557,7 +557,7 @@ bool ShouldUseViewsTaskManager() {
                                     column:[[tableColumn identifier] intValue]];
     buttonCell.attributedTitle = [[[NSAttributedString alloc]
         initWithString:title
-            attributes:@{NSForegroundColorAttributeName : [NSColor blackColor]}]
+            attributes:@{NSForegroundColorAttributeName : [NSColor labelColor]}]
         autorelease];
     buttonCell.image =
         taskManagerMac_->GetImageForRow(viewToModelMap_[rowIndex]);