Fix the TabScrubber always starting from the first tab in full screen mode.

chrome/browser/ui/views/ash/tab_scrubber.cc

Index: chrome/browser/ui/views/ash/tab_scrubber.cc
diff --git a/chrome/browser/ui/views/ash/tab_scrubber.cc b/chrome/browser/ui/views/ash/tab_scrubber.cc
index 72b39b71878fffd6f2185851403fb9db477dcf75..45eb1abae9bf0fbc36dc6d3c8f3c703dc240c210 100644
--- a/chrome/browser/ui/views/ash/tab_scrubber.cc
+++ b/chrome/browser/ui/views/ash/tab_scrubber.cc
@@ -234,9 +234,9 @@ void TabScrubber::BeginScrub(Browser* browser,
   browser_ = browser;
   tab_strip_ = browser_view->tabstrip();
 
-  Direction direction = (x_offset < 0) ? LEFT : RIGHT;
-  ScrubDirectionChanged(direction);
-
+  // The browser's top view must be revealed first, before we attempt to get the
+  // start point, otherwise that tab's bounds we get in GetStartPoint() will be
+  // wrong.

[James Cook, 2017/01/27 23:21:27]

nice comment

[afakhry, 2017/01/28 00:48:21]

Thanks!

   ImmersiveModeController* immersive_controller =
       browser_view->immersive_mode_controller();
   if (immersive_controller->IsEnabled()) {
@@ -244,6 +244,9 @@ void TabScrubber::BeginScrub(Browser* browser,
         ImmersiveModeController::ANIMATE_REVEAL_YES));
   }
 
+  Direction direction = (x_offset < 0) ? LEFT : RIGHT;
+  ScrubDirectionChanged(direction);
+
   tab_strip_->AddObserver(this);
 }