Make sure collapsed tabs are not visible.

Fixes a bug where a clipped favicon was sometimes visible in a collapsed
tab even when the tab is collapsed.

Tabs which are in collapsed groups *and* which are zero-width (so not
counting tabs which are animating to or from the collapsed state) now
cause TabStrip::ShouldTabBeVisible() to return false.

Bug: 1094051
Change-Id: Ie696a6e8442f6a4a761b7dee279da2e1a96ea1e6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2251738
Commit-Queue: Charlene Yan <cyan@chromium.org>
Reviewed-by: Charlene Yan <cyan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#779843}

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

@@ -1380,6 +1380,11 @@ bool TabStrip::ShouldTabBeVisible(const Tab* tab) const {
   if (tab->detached())
     return false;
 
+  if (tab->group() && controller()->IsGroupCollapsed(*tab->group()) &&
+      tab->bounds().IsEmpty()) {
+    return false;
+  }
+
   // When stacking tabs, all tabs should always be visible.
   if (stacked_layout_)
     return true;