Remove hover highlight on Harmony checkboxes.

ui/views/controls/button/checkbox.h

Index: ui/views/controls/button/checkbox.h
diff --git a/ui/views/controls/button/checkbox.h b/ui/views/controls/button/checkbox.h
index 6b336c6038dc57c5c56e692ed0d225e08c9b5a1b..4a965ac50e541fcbfe4debda81cbbee195e27c69 100644
--- a/ui/views/controls/button/checkbox.h
+++ b/ui/views/controls/button/checkbox.h
@@ -40,7 +40,7 @@ class VIEWS_EXPORT Checkbox : public LabelButton {
   // Returns whether MD is enabled; exists for the sake of brevity.
   static bool UseMd();
 
-  // Overridden from LabelButton:
+  // LabelButton:
   const char* GetClassName() const override;
   void GetAccessibleNodeData(ui::AXNodeData* node_data) override;
   void OnPaint(gfx::Canvas* canvas) override;
@@ -48,6 +48,7 @@ class VIEWS_EXPORT Checkbox : public LabelButton {
   void OnBlur() override;
   void OnNativeThemeChanged(const ui::NativeTheme* theme) override;
   std::unique_ptr<InkDropRipple> CreateInkDropRipple() const override;
+  std::unique_ptr<InkDropHighlight> CreateInkDropHighlight() const override;
   SkColor GetInkDropBaseColor() const override;
   gfx::ImageSkia GetImage(ButtonState for_state) const override;
 
@@ -65,7 +66,7 @@ class VIEWS_EXPORT Checkbox : public LabelButton {
   virtual const gfx::VectorIcon& GetVectorIcon() const;
 
  private:
-  // Overridden from Button:
+  // Button:
   void NotifyClick(const ui::Event& event) override;
 
   ui::NativeTheme::Part GetThemePart() const override;