Fix getting BrowserActionsContainer target width when animating

The target width can be set to zero when the action bar has no
icons. Zero in this case is a valid target width that should be
used instead of the current width when animating.

BUG=831560

Change-Id: Ib6604a9c56a6b922025cd3d3bce2773f78d3eda4
Reviewed-on: https://chromium-review.googlesource.com/1008871
Commit-Queue: Ahmed Fakhry <afakhry@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#550658}

chrome/browser/ui/views/toolbar/browser_actions_container.cc

@@ -247,12 +247,11 @@ void BrowserActionsContainer::ResizeAndAnimate(gfx::Tween::Type tween_type,
 int BrowserActionsContainer::GetWidth(GetWidthTime get_width_time) const {
   // This call originates from ToolbarActionsBar which wants to know how much
   // space is / will be used for action icons (excluding the separator).
-  const int width_without_separator =
-      (get_width_time == GET_WIDTH_AFTER_ANIMATION && animation_target_size_ > 0
-           ? animation_target_size_
-           : width()) -
-      GetSeparatorAreaWidth();
-
+  const int target_width =
+      get_width_time == GET_WIDTH_AFTER_ANIMATION && animating()
+          ? animation_target_size_
+          : width();
+  const int width_without_separator = target_width - GetSeparatorAreaWidth();
   return std::max(0, width_without_separator);
 }