CustomButton cleanup: make protected members private, create accessors

chrome/browser/ui/views/tabs/tab_strip.cc

Index: chrome/browser/ui/views/tabs/tab_strip.cc
diff --git a/chrome/browser/ui/views/tabs/tab_strip.cc b/chrome/browser/ui/views/tabs/tab_strip.cc
index 99b804179e95f6b799f31577b89dc624f6bb4b6e..bbfb7e82c39e1dafa9a46fa9f8ce87d3d579707f 100644
--- a/chrome/browser/ui/views/tabs/tab_strip.cc
+++ b/chrome/browser/ui/views/tabs/tab_strip.cc
@@ -308,7 +308,6 @@ class NewTabButton : public views::ImageButton,
   // Paints the fill region of the button into |canvas|, according to the
   // supplied values from GetImage() and the given |fill| path.
   void PaintFill(bool pressed,
-                 double hover_value,
                  float scale,
                  const SkPath& fill,
                  gfx::Canvas* canvas) const;
@@ -372,10 +371,6 @@ void NewTabButton::OnPaint(gfx::Canvas* canvas) {
   canvas->Translate(gfx::Vector2d(0, height() - kNewTabButtonHeight));
 
   const bool pressed = state() == views::CustomButton::STATE_PRESSED;
-  double hover_value =
-      (state() == views::CustomButton::STATE_HOVERED) ? 1 : 0;
-  if (hover_animation_->is_animating())
-    hover_value = hover_animation_->GetCurrentValue();
   const float scale = canvas->image_scale();
 
   SkPath fill;
@@ -392,7 +387,7 @@ void NewTabButton::OnPaint(gfx::Canvas* canvas) {
     fill.rLineTo(5.75 * scale, 12.5 * scale);
     fill.rCubicTo(0, 0.5 * scale, -0.25 * scale, scale, -scale, scale);
     fill.close();
-    PaintFill(pressed, hover_value, scale, fill, canvas);
+    PaintFill(pressed, scale, fill, canvas);
 
     // Stroke.
     gfx::ScopedCanvas scoped_canvas(canvas);
@@ -423,7 +418,7 @@ void NewTabButton::OnPaint(gfx::Canvas* canvas) {
     const float fill_canvas_scale = mask->HasRepresentation(scale) ?
         scale : ui::GetScaleForScaleFactor(ui::SCALE_FACTOR_100P);
     gfx::Canvas fill_canvas(GetNewTabButtonSize(), fill_canvas_scale, false);
-    PaintFill(pressed, hover_value, fill_canvas_scale, fill, &fill_canvas);
+    PaintFill(pressed, fill_canvas_scale, fill, &fill_canvas);
     gfx::ImageSkia image(fill_canvas.ExtractImageRep());
     canvas->DrawImageInt(
         gfx::ImageSkiaOperations::CreateMaskedImage(image, *mask), 0, 0);
@@ -511,7 +506,6 @@ void NewTabButton::GetBorderPath(float button_y,
 }
 
 void NewTabButton::PaintFill(bool pressed,
-                             double hover_value,
                              float scale,
                              const SkPath& fill,
                              gfx::Canvas* canvas) const {
@@ -591,12 +585,10 @@ void NewTabButton::PaintFill(bool pressed,
   }
 
   // White highlight on hover.
-  if (hover_value) {
-    const int alpha =
-        gfx::Tween::LinearIntValueBetween(hover_value, 0x00, md ? 0x4D : 0x40);
-    canvas->FillRect(GetLocalBounds(),
-                     SkColorSetA(SK_ColorWHITE, static_cast<SkAlpha>(alpha)));
-  }
+  const SkAlpha alpha = static_cast<SkAlpha>(
+      hover_animation().CurrentValueBetween(0x00, md ? 0x4D : 0x40));
+  if (alpha != SK_AlphaTRANSPARENT)

[Peter Kasting, 2015/12/21 20:34:18]

I suspect that Skia detects a transparent fill and bails, so we could probably
remove this conditional if you want, but it's fine either way.

[Evan Stade, 2015/12/21 22:27:16]

I followed the callstack for a while and couldn't see any obvious early returns.
Even if it does at some deep layer do nothing, it still does a good bit of work
before figuring that out.

+    canvas->FillRect(GetLocalBounds(), SkColorSetA(SK_ColorWHITE, alpha));
 
   // For MD, most states' opacities are adjusted using an opacity recorder in
   // TabStrip::PaintChildren(), but the pressed state is excluded there and