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

chrome/browser/ui/views/chooser_content_view.cc

Index: chrome/browser/ui/views/chooser_content_view.cc
diff --git a/chrome/browser/ui/views/chooser_content_view.cc b/chrome/browser/ui/views/chooser_content_view.cc
index 6d087eadfbd37c96b6bafd5fd56dd7c4ef363fee..76d76353e2f476bfed2bea2afda2c2ac09a42fa6 100644
--- a/chrome/browser/ui/views/chooser_content_view.cc
+++ b/chrome/browser/ui/views/chooser_content_view.cc
@@ -6,7 +6,10 @@
 
 #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"
@@ -21,6 +24,11 @@ const int kChooserHeight = 220;
 
 const int kThrobberDiameter = 24;
 
+// The lookup table for strength bar image.
+const int strength_bar_ids[5] = {IDR_SIGNAL_0_BAR, IDR_SIGNAL_1_BAR,

[Jeffrey Yasskin, 2016/08/19 17:46:54]

Name this kStrengthBarIds:
https://google.github.io/styleguide/cppguide.html#Constant_Names

[juncai, 2016/08/19 22:59:17]

Done.

+                                 IDR_SIGNAL_2_BAR, IDR_SIGNAL_3_BAR,
+                                 IDR_SIGNAL_4_BAR};
+
 }  // namespace
 
 ChooserContentView::ChooserContentView(
@@ -30,8 +38,11 @@ ChooserContentView::ChooserContentView(
   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 */);

[Jeffrey Yasskin, 2016/08/19 17:46:54]

Thanks for the comment about what the boolean means.

[juncai, 2016/08/19 22:59:17]

Acknowledged.

   table_view_->set_select_on_remove(false);
   table_view_->SetObserver(table_view_observer);
   table_view_->SetEnabled(chooser_controller_->NumOptions() > 0);
@@ -82,6 +93,31 @@ base::string16 ChooserContentView::GetText(int row, int column_id) {
 
 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(static_cast<size_t>(row));

[Jeffrey Yasskin, 2016/08/19 17:46:54]

You can let this be an implicit cast. The DCHECK_GE(row, 0) makes sure it's in
bounds for size_t.

[juncai, 2016/08/19 22:59:17]

Done.

+
+  if (level == -1)
+    return gfx::ImageSkia();
+
+  DCHECK_GE(level, 0);
+  DCHECK_LT(level, base::checked_cast<int>(arraysize(strength_bar_ids)));

[Jeffrey Yasskin, 2016/08/19 17:46:54]

You can omit the checked_cast here: you know this arraysize fits into an int.

[juncai, 2016/08/19 22:59:17]

Changed to static_cast<int> here, since if not using it, got compile error:
error: comparison of integers of different signs: 'const int' and 'const
unsigned long'

Done.

+
+  return *ResourceBundle::GetSharedInstance().GetImageSkiaNamed(

[Jeffrey Yasskin, 2016/08/19 17:46:54]

Can GetImageSkiaNamed ever return null?

[juncai, 2016/08/19 22:59:17]

From:
https://cs.chromium.org/chromium/src/ui/base/resource/resource_bundle.cc?type...
https://cs.chromium.org/chromium/src/ui/gfx/image/image.cc?type=cs&sq=package...
It seems it doesn't return nullptr.

But added a DCHECK here to make sure.

+      strength_bar_ids[level]);
+}
+
 void ChooserContentView::OnOptionsInitialized() {
   table_view_->OnModelChanged();
   UpdateTableView();