suggest: remove unneeded tracking field

tracking_last_suggestion_ is no longer used in the class, remove it.

BUG=b:241321719

Change-Id: I17776de7ba1758f7b895802586fa4417a7e24632
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3809551
Commit-Queue: Curtis McMullan <curtismcmullan@chromium.org>
Reviewed-by: Darren Shen <shend@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1032423}

chrome/browser/ash/input_method/assistive_window_controller.cc

@@ -143,7 +143,6 @@ void AssistiveWindowController::AcceptSuggestion(
 void AssistiveWindowController::HideSuggestion() {
   suggestion_text_ = base::EmptyString16();
   confirmed_length_ = 0;
-  tracking_last_suggestion_ = false;
   if (suggestion_window_view_)
     suggestion_window_view_->GetWidget()->Close();
   if (grammar_suggestion_window_)
@@ -177,7 +176,6 @@ void AssistiveWindowController::ShowSuggestion(
     // Since there is only one suggestion text in ShowSuggestion, we default to
     // vertical layout.
     InitSuggestionWindow(ui::ime::SuggestionWindowView::Orientation::kVertical);
-  tracking_last_suggestion_ = suggestion_text_ == details.text;
   suggestion_text_ = details.text;
   confirmed_length_ = details.confirmed_length;
   suggestion_window_view_->Show(details);

chrome/browser/ash/input_method/assistive_window_controller.h

@@ -83,7 +83,6 @@ class AssistiveWindowController : public views::WidgetObserver,
   std::u16string suggestion_text_;
   size_t confirmed_length_ = 0;
   Bounds bounds_;
-  bool tracking_last_suggestion_ = false;
 };
 
 }  // namespace input_method