Adds a test: RoundedOmniboxPopupContentsViewTest.PopupMatchesLocationBarBackground

Follow-up to r546408.

Bug: 801583
Change-Id: I76d52b43a103e13054dc9286c9566da40e366661
Reviewed-on: https://chromium-review.googlesource.com/983085
Commit-Queue: Trent Apted <tapted@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#547680}

chrome/browser/ui/views/omnibox/omnibox_popup_contents_view_browsertest.cc

@@ -444,6 +444,36 @@ IN_PROC_BROWSER_TEST_P(RoundedOmniboxPopupContentsViewTest,
   EXPECT_TRUE(GetPopupWidget()->IsClosed());
 }
 
+// Check that, for the rounded popup, the location bar background (and the
+// background of the textfield it contains) changes when the popup opens, and
+// matches the popup background color.
+IN_PROC_BROWSER_TEST_P(RoundedOmniboxPopupContentsViewTest,
+                       PopupMatchesLocationBarBackground) {
+  const SkColor color_before_open = location_bar()->background()->get_color();
+  EXPECT_EQ(color_before_open, omnibox_view()->GetBackgroundColor());
+
+  CreatePopupForTestQuery();
+  const SkColor color_after_open = location_bar()->background()->get_color();
+
+  // Sanity check that the colors are different, otherwise this test will not be
+  // testing anything useful. It is possible that a particular theme could
+  // configure these colors to be the same. In that case, this test should be
+  // updated to detect that, or switch to a theme where they are different.
+  EXPECT_NE(color_before_open, color_after_open);
+
+  EXPECT_EQ(color_after_open, omnibox_view()->GetBackgroundColor());
+
+  // For the rounded popup, the background is hosted in the view that contains
+  // the results area.
+  views::View* background_host = popup_view()->parent();
+  EXPECT_EQ(color_after_open, background_host->background()->get_color());
+
+  // Closing the popup should restore the original colors.
+  edit_model()->StopAutocomplete();
+  EXPECT_EQ(color_before_open, location_bar()->background()->get_color());
+  EXPECT_EQ(color_before_open, omnibox_view()->GetBackgroundColor());
+}
+
 INSTANTIATE_TEST_CASE_P(,
                         OmniboxPopupContentsViewTest,
                         ::testing::Values(WIDE, NARROW, ROUNDED),