Add signal strength indicator icon to WebBluetooth chooser on non-Mac desktops

chrome/browser/ui/views/chooser_content_view.cc

 // Copyright 2016 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/chooser_content_view.h"
 
 #include "base/numerics/safe_conversions.h"
 #include "chrome/grit/generated_resources.h"
+#include "grit/ui_resources.h"
 #include "ui/base/l10n/l10n_util.h"
+#include "ui/base/resource/resource_bundle.h"
+#include "ui/gfx/image/image_skia.h"
 #include "ui/views/controls/link.h"
 #include "ui/views/controls/styled_label.h"
 #include "ui/views/controls/table/table_view.h"
 #include "ui/views/controls/throbber.h"
 #include "ui/views/layout/fill_layout.h"
 
 namespace {
 
 const int kChooserWidth = 330;
 
 const int kChooserHeight = 220;
 
 const int kThrobberDiameter = 24;
 
+// The lookup table for signal strength level image.
+const int kSignalStrengthLevelImageIds[5] = {IDR_SIGNAL_0_BAR, IDR_SIGNAL_1_BAR,
+                                             IDR_SIGNAL_2_BAR, IDR_SIGNAL_3_BAR,
+                                             IDR_SIGNAL_4_BAR};
+
 }  // namespace
 
 ChooserContentView::ChooserContentView(
     views::TableViewObserver* table_view_observer,
     std::unique_ptr<ChooserController> chooser_controller)
     : chooser_controller_(std::move(chooser_controller)) {
   chooser_controller_->set_view(this);
   std::vector<ui::TableColumn> table_columns;
   table_columns.push_back(ui::TableColumn());
-  table_view_ =
-      new views::TableView(this, table_columns, views::TEXT_ONLY, true);
+  table_view_ = new views::TableView(
+      this, table_columns,
+      chooser_controller_->ShouldShowIconBeforeText() ? views::ICON_AND_TEXT
+                                                      : views::TEXT_ONLY,
+      true /* single_selection */);
   table_view_->set_select_on_remove(false);
   table_view_->SetObserver(table_view_observer);
   table_view_->SetEnabled(chooser_controller_->NumOptions() > 0);
 
   SetLayoutManager(new views::FillLayout());
   views::View* table_parent = table_view_->CreateParentIfNecessary();
   AddChildView(table_parent);
 
   throbber_ = new views::Throbber();
   // Set the throbber in the center of the chooser.
@@ skipping 30 matching lines @@
     return chooser_controller_->GetNoOptionsText();
   }
 
   DCHECK_GE(row, 0);
   DCHECK_LT(row, num_options);
   return chooser_controller_->GetOption(static_cast<size_t>(row));
 }
 
 void ChooserContentView::SetObserver(ui::TableModelObserver* observer) {}
 
+gfx::ImageSkia ChooserContentView::GetIcon(int row) {
+  DCHECK(chooser_controller_->ShouldShowIconBeforeText());
+
+  size_t num_options = chooser_controller_->NumOptions();
+  if (num_options == 0) {
+    DCHECK_EQ(0, row);
+    return gfx::ImageSkia();
+  }
+
+  DCHECK_GE(row, 0);
+  DCHECK_LT(row, base::checked_cast<int>(num_options));
+
+  int level = chooser_controller_->GetSignalStrengthLevel(row);
+
+  if (level == -1)
+    return gfx::ImageSkia();
+
+  DCHECK_GE(level, 0);
+  DCHECK_LT(level, static_cast<int>(arraysize(kSignalStrengthLevelImageIds)));
+
+  gfx::ImageSkia* image = ResourceBundle::GetSharedInstance().GetImageSkiaNamed(
+      kSignalStrengthLevelImageIds[level]);
+
+  DCHECK(image);

[Jeffrey Yasskin, 2016/08/20 00:03:29]

The dereference into a return by value is an implicit CHECK(), so you don't need
the DCHECK. I just wanted to make sure we didn't need to handle null by doing
something other than crashing.

[juncai, 2016/08/20 01:17:02]

Done.

+
+  return *image;
+}
+
 void ChooserContentView::OnOptionsInitialized() {
   table_view_->OnModelChanged();
   UpdateTableView();
 }
 
 void ChooserContentView::OnOptionAdded(size_t index) {
   table_view_->OnItemsAdded(base::checked_cast<int>(index), 1);
   UpdateTableView();
   table_view_->SetVisible(true);
   throbber_->SetVisible(false);
@@ skipping 114 matching lines @@
 }
 
 void ChooserContentView::UpdateTableView() {
   if (chooser_controller_->NumOptions() == 0) {
     table_view_->OnModelChanged();
     table_view_->SetEnabled(false);
   } else {
     table_view_->SetEnabled(true);
   }
 }