Respect "prefers reduced motion" option in the location bar by disabling icon label animations

This CL updates label icons to no longer perform the text "slide"
animation when the OS accessibility setting "prefers reduced motion"
is enabled.

Before:
https://bugs.chromium.org/p/chromium/issues/attachment?aid=417373&signed_aid=t0VJYHPUtkw0z1lDKkbiVA==&inline=1
After:
https://bugs.chromium.org/p/chromium/issues/attachment?aid=417374&signed_aid=5yX5WthdugQRYA75A6Ua8A==&inline=1

Change-Id: I79ede8bfec7c0c13b9678e2374ba16ec1aefee7e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1871504
Commit-Queue: Alan Cutter <alancutter@chromium.org>
Reviewed-by: Evan Stade <estade@chromium.org>
Reviewed-by: Robert Flack <flackr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#708441}

chrome/browser/ui/views/location_bar/icon_label_bubble_view.cc

@@ -211,6 +211,11 @@ bool IconLabelBubbleView::ShouldShowSeparator() const {
 }
 
 double IconLabelBubbleView::WidthMultiplier() const {
+  // TODO(https://crbug.com/8944): Disable animations globally instead of having
+  // piecemeal opt ins for respecting prefers reduced motion.
+  if (gfx::Animation::PrefersReducedMotion())
+    return 1.0;
+
   if (!slide_animation_.is_animating() && !is_animation_paused_)
     return 1.0;
 

ui/gfx/animation/animation.cc

@@ -141,13 +141,15 @@ void Animation::UpdatePrefersReducedMotion() {
 
 // static
 bool Animation::PrefersReducedMotion() {
+  if (!prefers_reduced_motion_.has_value()) {
     if (base::CommandLine::ForCurrentProcess()->HasSwitch(
             switches::kForcePrefersReducedMotion)) {
-    return true;
-  }
-  if (!prefers_reduced_motion_)
+      prefers_reduced_motion_ = true;
+    } else {
       UpdatePrefersReducedMotion();
-  return *prefers_reduced_motion_;
+    }
+  }
+  return prefers_reduced_motion_.value();
 }
 
 bool Animation::ShouldSendCanceledFromStop() {