Fix scrollbar buttons at hidpi when enable-use-zoom-for-dsf is on.

third_party/WebKit/Source/platform/scroll/ScrollbarThemeAuraTest.cpp

+// 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 "platform/scroll/ScrollbarThemeAura.h"
+
+#include "platform/scroll/ScrollbarTestSuite.h"
+
+namespace blink {
+
+using testing::Return;
+
+class ScrollbarThemeAuraTest : public ScrollbarTestSuite {
+protected:
+    void setMockScrollableAreaExpectations(MockScrollableArea* mock)
+    {
+        EXPECT_CALL(*mock, layerForHorizontalScrollbar())

[jbroman, 2016/05/11 21:24:08]

Is it important for these tests that this be a non-composited thing? If not, I'd
suggest using ON_CALL instead:

ON_CALL(*mock, layerForHorizontalScrollbar())
    .WillByDefault(Return(nullptr));

...that is, if that isn't already the default. It seems wrong to have an
expectation that sizing buttons checks whether scrollbars have a layer.

[Bret, 2016/05/12 00:18:12]

Hmm, okay I deleted this block. I added it originally to get rid of the gmock
warnings, but based on what they say and what you said I guess it's better to
ignore them. Seems weird to just leave warnings though.

+            .WillRepeatedly(Return(nullptr));
+        EXPECT_CALL(*mock, layerForVerticalScrollbar())
+            .WillRepeatedly(Return(nullptr));
+    }
+};
+
+TEST_F(ScrollbarThemeAuraTest, ButtonSizeHorizontal)
+{
+    MockScrollableArea* mockScrollableArea = MockScrollableArea::create();
+    setMockScrollableAreaExpectations(mockScrollableArea);
+    ScrollbarThemeMock mockTheme;
+    Scrollbar* scrollbar = Scrollbar::createForTesting(
+        mockScrollableArea, HorizontalScrollbar, RegularScrollbar, &mockTheme);
+    ScrollbarThemeAura theme;
+
+    IntRect scrollbarSizeNormalDimensions(11, 22, 444, 66);
+    scrollbar->setFrameRect(scrollbarSizeNormalDimensions);
+    IntSize size1 = theme.buttonSize(*scrollbar);
+    EXPECT_EQ(66, size1.width());
+    EXPECT_EQ(66, size1.height());
+
+    IntRect scrollbarSizeSquashedDimensions(11, 22, 444, 666);
+    scrollbar->setFrameRect(scrollbarSizeSquashedDimensions);
+    IntSize size2 = theme.buttonSize(*scrollbar);
+    EXPECT_EQ(222, size2.width());
+    EXPECT_EQ(666, size2.height());
+
+    ThreadHeap::collectAllGarbage();
+}
+
+TEST_F(ScrollbarThemeAuraTest, ButtonSizeVertical)
+{
+    MockScrollableArea* mockScrollableArea = MockScrollableArea::create();
+    setMockScrollableAreaExpectations(mockScrollableArea);
+    ScrollbarThemeMock mockTheme;
+    Scrollbar* scrollbar = Scrollbar::createForTesting(
+        mockScrollableArea, VerticalScrollbar, RegularScrollbar, &mockTheme);
+    ScrollbarThemeAura theme;
+
+    IntRect scrollbarSizeNormalDimensions(11, 22, 44, 666);
+    scrollbar->setFrameRect(scrollbarSizeNormalDimensions);
+    IntSize size1 = theme.buttonSize(*scrollbar);
+    EXPECT_EQ(44, size1.width());
+    EXPECT_EQ(44, size1.height());
+
+    IntRect scrollbarSizeSquashedDimensions(11, 22, 444, 666);
+    scrollbar->setFrameRect(scrollbarSizeSquashedDimensions);
+    IntSize size2 = theme.buttonSize(*scrollbar);
+    EXPECT_EQ(444, size2.width());
+    EXPECT_EQ(333, size2.height());
+
+    ThreadHeap::collectAllGarbage();
+}
+
+} // namespace blink