Update omnibox dropdown selection/hover background drawing for MD.

components/omnibox/browser/omnibox_popup_model.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 "components/omnibox/browser/omnibox_popup_model.h"
 
 #include <algorithm>
 
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 93 matching lines @@
   return view_->IsOpen();
 }
 
 void OmniboxPopupModel::SetHoveredLine(size_t line) {
   const bool is_disabling = (line == kNoMatch);
   DCHECK(is_disabling || (line < result().size()));
 
   if (line == hovered_line_)
     return;  // Nothing to do
 
+  // We need to update |hovered_line_| before calling InvalidateLine(), since it
+  // will check it to determine how to draw.
+  const size_t prev_hovered_line = hovered_line_;
+  hovered_line_ = line;
+
   // Make sure the old hovered line is redrawn.  No need to redraw the selected
   // line since selection overrides hover so the appearance won't change.
-  if ((hovered_line_ != kNoMatch) && (hovered_line_ != selected_line_))
-    view_->InvalidateLine(hovered_line_);
+  if ((prev_hovered_line != kNoMatch) && (prev_hovered_line != selected_line_))
+    view_->InvalidateLine(prev_hovered_line);
 
-  // Change the hover to the new line.
-  hovered_line_ = line;
   if (!is_disabling && (hovered_line_ != selected_line_))
     view_->InvalidateLine(hovered_line_);
 }
 
 void OmniboxPopupModel::SetSelectedLine(size_t line,
                                         bool reset_to_default,
                                         bool force) {
   const AutocompleteResult& result = this->result();
   if (result.empty())
     return;
@@ skipping 160 matching lines @@
 }
 
 void OmniboxPopupModel::RemoveObserver(OmniboxPopupModelObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
 void OmniboxPopupModel::SetAnswerBitmap(const SkBitmap& bitmap) {
   answer_bitmap_ = bitmap;
   view_->UpdatePopupAppearance();
 }