Fix tab grab width for apps with tabs

Ensures that apps with tabs still have the expected
tab grab width.

Bug: 846546
Change-Id: I43660db954cceb7097bae7998f030da2aa5e22cc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1763269
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#689169}

chrome/browser/ui/views/frame/browser_non_client_frame_view_ash.cc

@@ -668,9 +668,12 @@ int BrowserNonClientFrameViewAsh::GetTabStripLeftInset() const {
 }
 
 int BrowserNonClientFrameViewAsh::GetTabStripRightInset() const {
-  return ShouldShowCaptionButtons()
-             ? caption_button_container_->GetPreferredSize().width()
-             : 0;
+  int inset = 0;
+  if (ShouldShowCaptionButtons())
+    inset += caption_button_container_->GetPreferredSize().width();
+  if (hosted_app_button_container())
+    inset += hosted_app_button_container()->GetPreferredSize().width();
+  return inset;
 }
 
 bool BrowserNonClientFrameViewAsh::ShouldPaint() const {