Address some TODOs for ChooserBubbleDelegate class

chrome/browser/ui/cocoa/website_settings/chooser_bubble_ui_cocoa.mm

Index: chrome/browser/ui/cocoa/website_settings/chooser_bubble_ui_cocoa.mm
diff --git a/chrome/browser/ui/cocoa/website_settings/chooser_bubble_ui_cocoa.mm b/chrome/browser/ui/cocoa/website_settings/chooser_bubble_ui_cocoa.mm
index 2e8b819bf58c481519bbb60bad34214aa52dc2d6..e6205183cc9c052c1ef7671ba94b7443ad3d80b2 100644
--- a/chrome/browser/ui/cocoa/website_settings/chooser_bubble_ui_cocoa.mm
+++ b/chrome/browser/ui/cocoa/website_settings/chooser_bubble_ui_cocoa.mm
@@ -294,27 +294,22 @@ scoped_ptr<BubbleUi> ChooserBubbleDelegate::BuildBubbleUi() {
 }
 
 - (NSInteger)numberOfRowsInTableView:(NSTableView*)tableView {
-  const std::vector<base::string16>& device_names =
-      chooserBubbleDelegate_->GetOptions();
-  if (device_names.empty()) {
-    return 1;
-  } else {
-    return static_cast<NSInteger>(device_names.size());
-  }
+  size_t num_options = chooserBubbleDelegate_->NumOptions();
+  return num_options == 0 ? 1 : static_cast<NSInteger>(num_options);
 }
 
 - (id)tableView:(NSTableView*)tableView
     objectValueForTableColumn:(NSTableColumn*)tableColumn
                           row:(NSInteger)rowIndex {
-  const std::vector<base::string16>& device_names =
-      chooserBubbleDelegate_->GetOptions();
-  if (device_names.empty()) {
+  NSInteger num_options =
+      static_cast<NSInteger>(chooserBubbleDelegate_->NumOptions());
+  if (num_options == 0) {
     DCHECK(rowIndex == 0);
     return l10n_util::GetNSString(IDS_CHOOSER_BUBBLE_NO_DEVICES_FOUND_PROMPT);
   } else {
-    if (rowIndex >= 0 &&
-        rowIndex < static_cast<NSInteger>(device_names.size())) {
-      return base::SysUTF16ToNSString(device_names[rowIndex]);
+    if (rowIndex >= 0 && rowIndex < num_options) {
+      return base::SysUTF16ToNSString(
+          chooserBubbleDelegate_->GetOption(static_cast<size_t>(rowIndex)));
     } else {
       return @"";
     }
@@ -346,9 +341,7 @@ scoped_ptr<BubbleUi> ChooserBubbleDelegate::BuildBubbleUi() {
 }
 
 - (void)updateTableView {
-  const std::vector<base::string16>& device_names =
-      chooserBubbleDelegate_->GetOptions();
-  [tableView_ setEnabled:!device_names.empty()];
+  [tableView_ setEnabled:chooserBubbleDelegate_->NumOptions()];

[Reilly Grant (use Gerrit), 2016/01/04 19:00:25]

Please explicitly compare this value to 0.

[juncai, 2016/01/04 19:35:55]

Done.

   [tableView_ reloadData];
 }
 
@@ -503,12 +496,12 @@ void ChooserBubbleUiCocoa::OnOptionsInitialized() {
   [chooser_bubble_ui_controller_ onOptionsInitialized];
 }
 
-void ChooserBubbleUiCocoa::OnOptionAdded(int index) {
-  [chooser_bubble_ui_controller_ onOptionAdded:index];
+void ChooserBubbleUiCocoa::OnOptionAdded(size_t index) {
+  [chooser_bubble_ui_controller_ onOptionAdded:static_cast<NSInteger>(index)];
 }
 
-void ChooserBubbleUiCocoa::OnOptionRemoved(int index) {
-  [chooser_bubble_ui_controller_ onOptionRemoved:index];
+void ChooserBubbleUiCocoa::OnOptionRemoved(size_t index) {
+  [chooser_bubble_ui_controller_ onOptionRemoved:static_cast<NSInteger>(index)];
 }
 
 void ChooserBubbleUiCocoa::OnBubbleClosing() {