Fix horizontal scroll tab-switching behavior on Linux

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

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/views/frame/browser_root_view.h"
 
 #include "chrome/browser/autocomplete/autocomplete_classifier.h"
 #include "chrome/browser/autocomplete/autocomplete_classifier_factory.h"
 #include "chrome/browser/defaults.h"
 #include "chrome/browser/profiles/profile.h"
@@ skipping 113 matching lines @@
   if (browser_defaults::kScrollEventChangesTab) {
     // Switch to the left/right tab if the wheel-scroll happens over the
     // tabstrip, or the empty space beside the tabstrip.
     views::View* hit_view = GetEventHandlerForPoint(event.location());
     int hittest =
         GetWidget()->non_client_view()->NonClientHitTest(event.location());
     if (tabstrip()->Contains(hit_view) ||
         hittest == HTCAPTION ||
         hittest == HTTOP) {
       int scroll_offset = abs(event.y_offset()) > abs(event.x_offset()) ?
-          event.y_offset() : -event.x_offset();
+          event.y_offset() : event.x_offset();
       Browser* browser = browser_view_->browser();
       TabStripModel* model = browser->tab_strip_model();
       // Switch to the next tab only if not at the end of the tab-strip.
       if (scroll_offset < 0 && model->active_index() + 1 < model->count()) {
         chrome::SelectNextTab(browser);
         return true;
       }
 
       // Switch to the previous tab only if not at the beginning of the
       // tab-strip.
@@ skipping 59 matching lines @@
       browser_view_->browser()->profile())->Classify(
           text, false, false, metrics::OmniboxEventProto::INVALID_SPEC, &match,
           nullptr);
   if (!match.destination_url.is_valid())
     return false;
 
   if (url)
     *url = match.destination_url;
   return true;
 }