[omnibox] Add OmniboxRowView to contain a header and OmniboxResultView

With the new suggestion headers that are coming, go/omniboxtransparency,
some rows are going to have need to paint headers above the
OmniboxResultView.

I considered adding the header to OmniboxResultView, but this didn't
make sense for reasons detailed in some in-code comments.

So I'm adding a new lightweight OmniboxRowView class to be a parent of
both the OmniboxResultView and the optional header View that sits right
above it.

The header View is not implemented yet.

Bug: 1052522
Change-Id: I693fa2dec0aa194da69f5fc744fe1099817f5ddd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2130814
Commit-Queue: Tommy Li <tommycli@chromium.org>
Reviewed-by: Justin Donnelly <jdonnelly@chromium.org>
Cr-Commit-Position: refs/heads/master@{#756803}

chrome/browser/ui/BUILD.gn

@@ -3140,6 +3140,8 @@ jumbo_static_library("ui") {
       "views/omnibox/omnibox_popup_contents_view.h",
       "views/omnibox/omnibox_result_view.cc",
       "views/omnibox/omnibox_result_view.h",
+      "views/omnibox/omnibox_row_view.cc",
+      "views/omnibox/omnibox_row_view.h",
       "views/omnibox/omnibox_tab_switch_button.cc",
       "views/omnibox/omnibox_tab_switch_button.h",
       "views/omnibox/omnibox_text_view.cc",

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

@@ -14,6 +14,7 @@
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/views/location_bar/location_bar_view.h"
 #include "chrome/browser/ui/views/omnibox/omnibox_result_view.h"
+#include "chrome/browser/ui/views/omnibox/omnibox_row_view.h"
 #include "chrome/browser/ui/views/omnibox/omnibox_view_views.h"
 #include "chrome/browser/ui/views/omnibox/rounded_omnibox_results_frame.h"
 #include "chrome/browser/ui/views/omnibox/webui_omnibox_popup_view.h"
@@ -207,7 +208,7 @@ OmniboxResultView* OmniboxPopupContentsView::result_view_at(size_t i) {
   if (i >= children().size())
     return nullptr;
 
-  return static_cast<OmniboxResultView*>(children()[i]);
+  return static_cast<OmniboxRowView*>(children()[i])->result_view();
 }
 
 bool OmniboxPopupContentsView::InExplicitExperimentalKeywordMode() {
@@ -303,19 +304,26 @@ void OmniboxPopupContentsView::UpdatePopupAppearance() {
       // be expensive to create due to loading font data, this saves time and
       // memory during browser startup.
       if (children().size() == i) {
-        AddChildView(std::make_unique<OmniboxResultView>(this, i));
+        AddChildView(std::make_unique<OmniboxRowView>(
+            std::make_unique<OmniboxResultView>(this, i)));
       }
 
-      OmniboxResultView* view = result_view_at(i);
+      OmniboxRowView* const row_view =
+          static_cast<OmniboxRowView*>(children()[i]);
+      row_view->SetVisible(true);
+
+      OmniboxResultView* const result_view = row_view->result_view();
       const AutocompleteMatch& match = GetMatchAtIndex(i);
-      view->SetMatch(match);
-      view->SetVisible(true);
+      result_view->SetMatch(match);
+
       const SkBitmap* bitmap = model_->RichSuggestionBitmapAt(i);
-      if (bitmap)
-        view->SetRichSuggestionImage(
+      if (bitmap) {
+        result_view->SetRichSuggestionImage(
             gfx::ImageSkia::CreateFrom1xBitmap(*bitmap));
+      }
     }
 
+    // If we have more views than matches, hide the surplus ones.
     for (auto i = children().begin() + result_size; i != children().end(); ++i)
       (*i)->SetVisible(false);
   }

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

+// Copyright 2020 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/omnibox/omnibox_row_view.h"
+
+#include "chrome/browser/ui/views/omnibox/omnibox_result_view.h"
+#include "ui/views/layout/box_layout.h"
+
+OmniboxRowView::OmniboxRowView(std::unique_ptr<OmniboxResultView> result_view) {
+  DCHECK(result_view);
+
+  SetLayoutManager(std::make_unique<views::BoxLayout>(
+      views::BoxLayout::Orientation::kVertical));
+
+  result_view_ = AddChildView(std::move(result_view));
+}
+
+void OmniboxRowView::SetHeader(base::Optional<int> suggestion_group_id,
+                               const base::string16& header_text) {
+  // TODO(tommycli): Create a child header view here. Not implemented yet.
+}

chrome/browser/ui/views/omnibox/omnibox_row_view.h

+// Copyright 2020 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.
+
+#ifndef CHROME_BROWSER_UI_VIEWS_OMNIBOX_OMNIBOX_ROW_VIEW_H_
+#define CHROME_BROWSER_UI_VIEWS_OMNIBOX_OMNIBOX_ROW_VIEW_H_
+
+#include "base/optional.h"
+#include "base/strings/string16.h"
+#include "ui/views/view.h"
+
+class OmniboxResultView;
+
+// The View that's a direct child of the OmniboxPopupContentsView, one per row.
+// This, in turn, has a child OmniboxResultView and an optional header that is
+// painted right above it. The header is not a child of OmniboxResultView
+// because it's logically not part of the result view:
+//  - Hovering the header doesn't highlight the result view.
+//  - Clicking the header doesn't navigate to the match.
+//  - It's the header for multiple matches, it's just painted above this row.
+class OmniboxRowView : public views::View {
+ public:
+  explicit OmniboxRowView(std::unique_ptr<OmniboxResultView> result_view);
+
+  // Sets the header that appears above this row. |suggestion_group_id| can be
+  // base::nullopt, and that will hide the header.
+  void SetHeader(base::Optional<int> suggestion_group_id,
+                 const base::string16& header_text);
+
+  // The result view associated with this row.
+  OmniboxResultView* result_view() const { return result_view_; }
+
+ private:
+  // Non-owning pointer to the result view for this row. This is never nullptr.
+  OmniboxResultView* result_view_;
+};
+
+#endif  // CHROME_BROWSER_UI_VIEWS_OMNIBOX_OMNIBOX_ROW_VIEW_H_