Fix horizontal scroll tab-switching behavior on Linux

The tab on the left side should be selected when scrolling to left and vice versa.

BUG=365501
TEST=Prepare a mouse with horizontal-scrolling feature, open multiple tabs, place cursor over tab strip and try to switch tabs.

Review URL: https://codereview.chromium.org/1084903002

Cr-Commit-Position: refs/heads/master@{#325260}

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

@@ -131,7 +131,7 @@ bool BrowserRootView::OnMouseWheel(const ui::MouseWheelEvent& event) {
         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.