Simplify default focus behavior definition

Use a variable instead of a static function to represent the default
focus behavior in platform style files.

Bug: 1001103
Change-Id: Icf92ea6b83037ba3b285ba0c5eccb7bc16f1f460
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2579653Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Commit-Queue: Wei Li <weili@chromium.org>
Cr-Commit-Position: refs/heads/master@{#835278}

docs/ui/input_event/index.md

@@ -377,7 +377,7 @@ in system settings needs to be enabled to have navigation of all controls on the
 screen.
 
 To comply with Mac’s behavior, Chrome sets
-[DefaultFocusBehavior() ](https://source.chromium.org/chromium/chromium/src/+/master:ui/views/style/platform_style_mac.mm;l=86)in
+[kDefaultFocusBehavior](https://source.chromium.org/chromium/chromium/src/+/master:ui/views/style/platform_style.h?q=kDefaultFocusBehavior) in
 the platform style to ACCESSIBLE_ONLY on Mac as opposed to ALWAYS on other
 platforms. Controls that are
 [marked](https://source.chromium.org/chromium/chromium/src/+/master:chrome/browser/ui/views/toolbar/toolbar_button.cc;drc=93819857a690b79b1524052513747846c068ca90;l=104)

ui/views/controls/button/button.cc

@@ -591,7 +591,7 @@ Button::Button(PressedCallback callback)
     : AnimationDelegateViews(this),
       callback_(std::move(callback)),
       ink_drop_base_color_(gfx::kPlaceholderColor) {
-  SetFocusBehavior(PlatformStyle::DefaultFocusBehavior());
+  SetFocusBehavior(PlatformStyle::kDefaultFocusBehavior);
   SetProperty(kIsButtonProperty, true);
   hover_animation_.SetSlideDuration(base::TimeDelta::FromMilliseconds(150));
   SetInstallFocusRingOnFocus(true);

ui/views/controls/button/image_button_unittest.cc

@@ -43,7 +43,7 @@ using ImageButtonTest = ViewsTestBase;
 TEST_F(ImageButtonTest, FocusBehavior) {
   ImageButton button;
 
-  EXPECT_EQ(PlatformStyle::DefaultFocusBehavior(), button.GetFocusBehavior());
+  EXPECT_EQ(PlatformStyle::kDefaultFocusBehavior, button.GetFocusBehavior());
 }
 
 TEST_F(ImageButtonTest, Basics) {

ui/views/controls/button/label_button_unittest.cc

@@ -143,7 +143,7 @@ class LabelButtonTest : public test::WidgetTest {
 };
 
 TEST_F(LabelButtonTest, FocusBehavior) {
-  EXPECT_EQ(PlatformStyle::DefaultFocusBehavior(), button_->GetFocusBehavior());
+  EXPECT_EQ(PlatformStyle::kDefaultFocusBehavior, button_->GetFocusBehavior());
 }
 
 TEST_F(LabelButtonTest, Init) {

ui/views/examples/button_example.cc

@@ -127,7 +127,7 @@ void ButtonExample::LabelButtonPressed(LabelButton* label_button,
       label_button->IsAccessibilityFocusable()
           ? label_button->SetFocusBehavior(View::FocusBehavior::NEVER)
           : label_button->SetFocusBehavior(
-                PlatformStyle::DefaultFocusBehavior());
+                PlatformStyle::kDefaultFocusBehavior);
     }
   } else if (event.IsAltDown()) {
     label_button->SetIsDefault(!label_button->GetIsDefault());

ui/views/style/platform_style.cc

@@ -50,6 +50,8 @@ const bool PlatformStyle::kUseRipples = true;
 const bool PlatformStyle::kTextfieldScrollsToStartOnFocusChange = false;
 const bool PlatformStyle::kTextfieldUsesDragCursorWhenDraggable = true;
 const bool PlatformStyle::kInactiveWidgetControlsAppearDisabled = false;
+const View::FocusBehavior PlatformStyle::kDefaultFocusBehavior =
+    View::FocusBehavior::ALWAYS;
 
 // Linux clips bubble windows that extend outside their parent window
 // bounds.
@@ -83,11 +85,6 @@ gfx::Range PlatformStyle::RangeToDeleteBackwards(const base::string16& text,
   return gfx::Range(cursor_position, previous_grapheme_index);
 }
 
-// static
-View::FocusBehavior PlatformStyle::DefaultFocusBehavior() {
-  return View::FocusBehavior::ALWAYS;
-}
-
 #endif  // OS_APPLE
 
 #if !BUILDFLAG(ENABLE_DESKTOP_AURA) || \

ui/views/style/platform_style.h

@@ -80,6 +80,9 @@ class VIEWS_EXPORT PlatformStyle {
   // for bubbles going off-screen to bring more bubble area into view.
   static const bool kAdjustBubbleIfOffscreen;
 
+  // Default focus behavior on the platform.
+  static const View::FocusBehavior kDefaultFocusBehavior;
+
   // Creates the default scrollbar for the given orientation.
   static std::unique_ptr<ScrollBar> CreateScrollBar(bool is_horizontal);
 
@@ -99,9 +102,6 @@ class VIEWS_EXPORT PlatformStyle {
   static gfx::Range RangeToDeleteBackwards(const base::string16& text,
                                            size_t cursor_position);
 
-  // Returns the default focus behavior based on the platform.
-  static View::FocusBehavior DefaultFocusBehavior();
-
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PlatformStyle);
 };

ui/views/style/platform_style_mac.mm

@@ -44,6 +44,8 @@ const bool PlatformStyle::kTreeViewSelectionPaintsEntireRow = true;
 const bool PlatformStyle::kUseRipples = false;
 const bool PlatformStyle::kInactiveWidgetControlsAppearDisabled = true;
 const bool PlatformStyle::kAdjustBubbleIfOffscreen = false;
+const View::FocusBehavior PlatformStyle::kDefaultFocusBehavior =
+    View::FocusBehavior::ACCESSIBLE_ONLY;
 
 const Button::KeyClickAction PlatformStyle::kKeyClickActionOnSpace =
     Button::KeyClickAction::kOnKeyPress;
@@ -82,9 +84,4 @@ gfx::Range PlatformStyle::RangeToDeleteBackwards(const base::string16& text,
                     range_to_delete.location);
 }
 
-// static
-View::FocusBehavior PlatformStyle::DefaultFocusBehavior() {
-  return View::FocusBehavior::ACCESSIBLE_ONLY;
-}
-
 }  // namespace views