Shorten tab hover animation from 400 ms to 200 ms.

Especially in refresh, 400 feels too slow.  In testing, 200 seemed much better.

BUG=none
TEST=none

Change-Id: Ib7a8519fac9baadbd6853d6b5810644e4e2b7433
Reviewed-on: https://chromium-review.googlesource.com/1107383Reviewed-by: Allen Bauer <kylixrd@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568869}

chrome/browser/ui/views/tabs/glow_hover_controller.cc

@@ -11,7 +11,7 @@ static const double kSubtleOpacityScale = 0.45;
 static const double kPronouncedOpacityScale = 1.0;
 
 // How long the hover state takes.
-static const int kTrackHoverDurationMs = 400;
+static const int kTrackHoverDurationMs = 200;
 
 GlowHoverController::GlowHoverController(views::View* view)
     : view_(view), animation_(this), opacity_scale_(kSubtleOpacityScale) {