Dynamically compute tab/frame separator color.

chrome/browser/themes/theme_service_unittest.cc

Index: chrome/browser/themes/theme_service_unittest.cc
diff --git a/chrome/browser/themes/theme_service_unittest.cc b/chrome/browser/themes/theme_service_unittest.cc
index 0900a4b942d81580a426ce7e1b51645a3b72fee0..127055d14fe6588a946e80f4b55ddaf859fae2c4 100644
--- a/chrome/browser/themes/theme_service_unittest.cc
+++ b/chrome/browser/themes/theme_service_unittest.cc
@@ -29,6 +29,7 @@
 #include "extensions/common/extension.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/base/material_design/material_design_controller.h"
+#include "ui/base/test/material_design_controller_test_api.h"
 
 #if defined(ENABLE_SUPERVISED_USERS)
 #include "chrome/browser/supervised_user/supervised_user_service.h"
@@ -45,6 +46,17 @@ class ThemeServiceTest : public extensions::ExtensionServiceTestBase {
                        registry_(NULL) {}
   ~ThemeServiceTest() override {}
 
+  void SetUp() override {
+    extensions::ExtensionServiceTestBase::SetUp();
+    extensions::ExtensionServiceTestBase::ExtensionServiceInitParams params =
+        CreateDefaultInitParams();
+    params.profile_is_supervised = is_supervised_;
+    InitializeExtensionService(params);
+    service_->Init();
+    registry_ = ExtensionRegistry::Get(profile_.get());
+    ASSERT_TRUE(registry_);
+  }
+
   // Moves a minimal theme to |temp_dir_path| and unpacks it from that
   // directory.
   std::string LoadUnpackedThemeAt(const base::FilePath& temp_dir) {
@@ -92,21 +104,20 @@ class ThemeServiceTest : public extensions::ExtensionServiceTestBase {
     base::MessageLoop::current()->RunUntilIdle();
   }
 
-  void SetUp() override {
-    extensions::ExtensionServiceTestBase::SetUp();
-    extensions::ExtensionServiceTestBase::ExtensionServiceInitParams params =
-        CreateDefaultInitParams();
-    params.profile_is_supervised = is_supervised_;
-    InitializeExtensionService(params);
-    service_->Init();
-    registry_ = ExtensionRegistry::Get(profile_.get());
-    ASSERT_TRUE(registry_);
-  }
-
   const CustomThemeSupplier* get_theme_supplier(ThemeService* theme_service) {
     return theme_service->get_theme_supplier();
   }
 
+  // Returns the separator color as the opaque result of blending it atop the
+  // frame color (which is the color we use when calculating the contrast of the
+  // separator with the tab and frame colors).
+  static SkColor GetSeparatorColor(SkColor tab_color, SkColor frame_color) {
+    const SkColor separator_color =
+        ThemeService::GetSeparatorColor(tab_color, frame_color);
+    return color_utils::AlphaBlend(SkColorSetA(separator_color, SK_AlphaOPAQUE),
+                                   frame_color, SkColorGetA(separator_color));
+  }
+
  protected:
   bool is_supervised_;
   ExtensionRegistry* registry_;
@@ -376,4 +387,89 @@ TEST_F(ThemeServiceSupervisedUserTest, SupervisedUserThemeReplacesNativeTheme) {
 #endif // defined(OS_LINUX) && !defined(OS_CHROMEOS)
 #endif // defined(ENABLE_SUPERVISED_USERS)
 
+// Simple class to run tests in material design mode.
+class ThemeServiceMaterialDesignTest : public ThemeServiceTest {
+ public:
+  void SetUp() override {
+    ThemeServiceTest::SetUp();
+    ui::test::MaterialDesignControllerTestAPI::SetMode(
+        ui::MaterialDesignController::MATERIAL_NORMAL);
+  }
+
+  void TearDown() override {
+    ThemeServiceTest::TearDown();
+    ui::test::MaterialDesignControllerTestAPI::UninitializeMode();
+  }
+};
+
+// Check that the function which computes the separator color behaves as
+// expected for a variety of inputs.  We run in material design mode so we can
+// use the material normal and incognito color combinations, which differ from
+// each other in ways that are interesting to test.
+TEST_F(ThemeServiceMaterialDesignTest, SeparatorColor) {
+  // For the default theme, the separator should darken the frame.
+  SkColor tab_color =
+      ThemeProperties::GetDefaultColor(ThemeProperties::COLOR_TOOLBAR, false);
+  SkColor frame_color =
+      ThemeProperties::GetDefaultColor(ThemeProperties::COLOR_FRAME, false);
+  SkColor separator_color = GetSeparatorColor(tab_color, frame_color);

[Evan Stade, 2016/03/15 19:05:06]

can you add a check to verify this matches what you get from
ThemeService::GetColor(COLOR_TOOLBAR_TOP_SEPARATOR)? It's annoying we have to
keep that in sync with ThemeProperties::GetDefaultColor but we can at least add
a test for it.

[Peter Kasting, 2016/03/16 03:12:59]

Sure.

+  double frame_luminance = color_utils::GetRelativeLuminance(frame_color);
+  EXPECT_LT(color_utils::GetRelativeLuminance(separator_color),
+            frame_luminance);
+
+  // If we reverse the colors, the separator should lighten the frame.
+  separator_color = GetSeparatorColor(frame_color, tab_color);
+  EXPECT_GT(color_utils::GetRelativeLuminance(separator_color),
+            frame_luminance);
+
+  // When the frame color is black, the separator should lighten the frame, but
+  // it should still be darker than the tab color.
+  separator_color = GetSeparatorColor(tab_color, SK_ColorBLACK);
+  double separator_luminance =
+      color_utils::GetRelativeLuminance(separator_color);
+  double tab_luminance = color_utils::GetRelativeLuminance(tab_color);
+  EXPECT_GT(separator_luminance, 0);
+  EXPECT_LT(separator_luminance, tab_luminance);
+
+  // When the frame color is white, the separator should darken the frame; it
+  // should also be lighter than the tab color since otherwise the contrast with
+  // the tab would be too minimal.
+  separator_color = GetSeparatorColor(tab_color, SK_ColorWHITE);
+  separator_luminance = color_utils::GetRelativeLuminance(separator_color);
+  EXPECT_LT(separator_luminance, 1);
+  EXPECT_LT(separator_luminance, tab_luminance);
+
+  // Likewise for the default incognito theme, the separator should darken the
+  // frame.
+  tab_color =
+      ThemeProperties::GetDefaultColor(ThemeProperties::COLOR_TOOLBAR, true);
+  frame_color =
+      ThemeProperties::GetDefaultColor(ThemeProperties::COLOR_FRAME, true);
+  separator_color = GetSeparatorColor(tab_color, frame_color);
+  frame_luminance = color_utils::GetRelativeLuminance(frame_color);
+  EXPECT_LT(color_utils::GetRelativeLuminance(separator_color),
+            frame_luminance);
+
+  // And if we reverse the colors, the separator should lighten the frame.
+  separator_color = GetSeparatorColor(frame_color, tab_color);
+  EXPECT_GT(color_utils::GetRelativeLuminance(separator_color),
+            frame_luminance);
+
+  // When the frame color is black, the separator should lighten the frame; it
+  // should also be lighter than the tab color since otherwise the contrast with
+  // the tab would be too minimal.
+  separator_color = GetSeparatorColor(tab_color, SK_ColorBLACK);
+  separator_luminance = color_utils::GetRelativeLuminance(separator_color);
+  tab_luminance = color_utils::GetRelativeLuminance(tab_color);
+  EXPECT_GT(separator_luminance, 0);
+  EXPECT_GT(separator_luminance, tab_luminance);
+
+  // When the frame color is white, the separator should darken the frame, but
+  // it should still be lighter than the tab color.
+  separator_color = GetSeparatorColor(tab_color, SK_ColorWHITE);
+  separator_luminance = color_utils::GetRelativeLuminance(separator_color);
+  EXPECT_LT(separator_luminance, 1);
+  EXPECT_GT(separator_luminance, tab_luminance);
+}
+
 }; // namespace theme_service_internal