Draw nicer arrows when the scrollbar buttons are not square.

ui/native_theme/native_theme_aura_unittest.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/native_theme/native_theme_aura.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/skia/include/core/SkPath.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/native_theme/native_theme.h"
@@ skipping 52 matching lines @@
   VerifyTriangle(path, SkPoint::Make(58, 76), SkPoint::Make(58, 85),
                  SkPoint::Make(63, 80.5));
 
   // Left arrow is just a flipped right arrow.
   path = theme->PathForArrow(gfx::Rect(20, 80, 17, 17),
                              NativeTheme::kScrollbarLeftArrow);
   VerifyTriangle(path, SkPoint::Make(30, 85), SkPoint::Make(30, 92),
                  SkPoint::Make(26, 88.5));
 }
 
+TEST(NativeThemeAuraTest, ArrowForNonSquareButton) {
+  NativeThemeAura* theme = NativeThemeAura::instance();
+  SkPath path = theme->PathForArrow(gfx::Rect(90, 80, 42, 37),
+                                    NativeTheme::kScrollbarLeftArrow);
+  VerifyTriangle(path, SkPoint::Make(116, 89), SkPoint::Make(116, 109),
+                 SkPoint::Make(105, 99));
+}
+
+TEST(NativeThemeAuraTest, BoundingRectSquare) {
+  NativeThemeAura* theme = NativeThemeAura::instance();
+  gfx::RectF bounding_rect =
+      theme->BoundingRectForArrow(gfx::Rect(42, 61, 21, 21));
+  EXPECT_EQ(48.f, bounding_rect.x());
+  EXPECT_EQ(67.f, bounding_rect.y());
+  EXPECT_EQ(9.f, bounding_rect.width());
+  EXPECT_EQ(bounding_rect.width(), bounding_rect.height());
+}
+
+TEST(NativeThemeAuraTest, BoundingRectSlightlyRectangular) {
+  NativeThemeAura* theme = NativeThemeAura::instance();
+
+  // Stretched horzontally.
+  gfx::RectF bounding_rect =
+      theme->BoundingRectForArrow(gfx::Rect(42, 61, 25, 20));
+  EXPECT_EQ(49.f, bounding_rect.x());
+  EXPECT_EQ(66.f, bounding_rect.y());
+  EXPECT_EQ(11.f, bounding_rect.width());
+  EXPECT_EQ(bounding_rect.width(), bounding_rect.height());
+
+  // Stretched vertically.
+  bounding_rect = theme->BoundingRectForArrow(gfx::Rect(42, 61, 14, 10));
+  EXPECT_EQ(46.f, bounding_rect.x());
+  EXPECT_EQ(63.f, bounding_rect.y());
+  EXPECT_EQ(6.f, bounding_rect.width());
+  EXPECT_EQ(bounding_rect.width(), bounding_rect.height());
+}
+
+TEST(NativeThemeAuraTest, BoundingRectVeryRectangular) {
+  NativeThemeAura* theme = NativeThemeAura::instance();
+
+  // Stretched horzontally.
+  gfx::RectF bounding_rect =
+      theme->BoundingRectForArrow(gfx::Rect(42, 61, 30, 8));
+  EXPECT_EQ(53.f, bounding_rect.x());
+  EXPECT_EQ(61.f, bounding_rect.y());
+  EXPECT_EQ(8.f, bounding_rect.width());
+  EXPECT_EQ(bounding_rect.width(), bounding_rect.height());
+
+  // Stretched vertically.
+  bounding_rect = theme->BoundingRectForArrow(gfx::Rect(42, 61, 6, 44));
+  EXPECT_EQ(42.f, bounding_rect.x());
+  EXPECT_EQ(80.f, bounding_rect.y());
+  EXPECT_EQ(6.f, bounding_rect.width());
+  EXPECT_EQ(bounding_rect.width(), bounding_rect.height());
+}
+
+TEST(NativeThemeAuraTest, BoundingRectSnappedToWholePixels) {
+  NativeThemeAura* theme = NativeThemeAura::instance();
+
+  gfx::RectF bounding_rect =
+      theme->BoundingRectForArrow(gfx::Rect(0, 0, 9, 10));
+  EXPECT_EQ(3.f, bounding_rect.x());
+
+  bounding_rect = theme->BoundingRectForArrow(gfx::Rect(0, 0, 10, 9));
+  EXPECT_EQ(3.f, bounding_rect.y());
+}
+
 }  // namespace ui