Use tab foreground color blended with the background color for separator.

Bug: 866689
Change-Id: I33ba303ddad0bec0de0624f98444c252ff5251ba
Reviewed-on: https://chromium-review.googlesource.com/1173752Reviewed-by: Bret Sepulveda <bsep@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#582922}

chrome/browser/ui/views/frame/browser_non_client_frame_view.cc

@@ -155,19 +155,6 @@ SkColor BrowserNonClientFrameView::GetToolbarTopSeparatorColor() const {
              : paint_color;
 }
 
-SkColor BrowserNonClientFrameView::GetTabSeparatorColor() const {
-  DCHECK(MD::IsRefreshUi());
-  // TODO(pkasting): https://crbug.com/866689  Replace this with "blend
-  // background tab text color toward background tab background color at 46% or
-  // 1.84 contrast ratio, whichever is larger" (and make sure the blend is large
-  // enough in the default theme to not need adjusting).
-  constexpr SkAlpha kTabSeparatorAlpha = 0x4D;  // 30%
-  const SkColor tab_color = GetTabBackgroundColor(TAB_INACTIVE, true);
-  const SkColor base_color =
-      color_utils::BlendTowardOppositeLuma(tab_color, SK_AlphaOPAQUE);
-  return color_utils::AlphaBlend(base_color, tab_color, kTabSeparatorAlpha);
-}
-
 SkColor BrowserNonClientFrameView::GetTabBackgroundColor(TabState state,
                                                          bool opaque) const {
   if (state == TAB_ACTIVE)

chrome/browser/ui/views/frame/browser_non_client_frame_view.h

@@ -93,9 +93,6 @@ class BrowserNonClientFrameView : public views::NonClientFrameView,
   // state of the window.
   SkColor GetToolbarTopSeparatorColor() const;
 
-  // Under Refresh, returns the color of the separator between the tabs.
-  SkColor GetTabSeparatorColor() const;
-
   // Returns the tab background color based on both the |state| of the tab and
   // the activation state of the window.  If |opaque| is true, the resulting
   // color after drawing the tab background on the frame will be returned.

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

@@ -398,10 +398,6 @@ SkColor BrowserTabStripController::GetToolbarTopSeparatorColor() const {
   return GetFrameView()->GetToolbarTopSeparatorColor();
 }
 
-SkColor BrowserTabStripController::GetTabSeparatorColor() const {
-  return GetFrameView()->GetTabSeparatorColor();
-}
-
 SkColor BrowserTabStripController::GetTabBackgroundColor(TabState state,
                                                          bool opaque) const {
   return GetFrameView()->GetTabBackgroundColor(state, opaque);

chrome/browser/ui/views/tabs/browser_tab_strip_controller.h

@@ -79,7 +79,6 @@ class BrowserTabStripController : public TabStripController,
   bool HasVisibleBackgroundTabShapes() const override;
   SkColor GetFrameColor() const override;
   SkColor GetToolbarTopSeparatorColor() const override;
-  SkColor GetTabSeparatorColor() const override;
   SkColor GetTabBackgroundColor(TabState active, bool opaque) const override;
   SkColor GetTabForegroundColor(TabState state) const override;
   int GetTabBackgroundResourceId(bool* has_custom_image) const override;

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

@@ -162,10 +162,6 @@ SkColor FakeBaseTabStripController::GetToolbarTopSeparatorColor() const {
   return gfx::kPlaceholderColor;
 }
 
-SkColor FakeBaseTabStripController::GetTabSeparatorColor() const {
-  return gfx::kPlaceholderColor;
-}
-
 SkColor FakeBaseTabStripController::GetTabBackgroundColor(TabState state,
                                                           bool opaque) const {
   return gfx::kPlaceholderColor;

chrome/browser/ui/views/tabs/fake_base_tab_strip_controller.h

@@ -55,7 +55,6 @@ class FakeBaseTabStripController : public TabStripController {
   bool HasVisibleBackgroundTabShapes() const override;
   SkColor GetFrameColor() const override;
   SkColor GetToolbarTopSeparatorColor() const override;
-  SkColor GetTabSeparatorColor() const override;
   SkColor GetTabBackgroundColor(TabState state, bool opaque) const override;
   SkColor GetTabForegroundColor(TabState state) const override;
   int GetTabBackgroundResourceId(bool* has_custom_image) const override;

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

@@ -319,7 +319,7 @@ void TabStrip::FrameColorsChanged() {
   for (int i = 0; i < tab_count(); ++i)
     tab_at(i)->FrameColorsChanged();
   new_tab_button_->FrameColorsChanged();
-  UpdateOpacities();
+  UpdateContrastRatioValues();
   SchedulePaint();
 }
 
@@ -1144,7 +1144,7 @@ SkColor TabStrip::GetToolbarTopSeparatorColor() const {
 }
 
 SkColor TabStrip::GetTabSeparatorColor() const {
-  return controller_->GetTabSeparatorColor();
+  return separator_color_;
 }
 
 SkColor TabStrip::GetTabBackgroundColor(TabState state, bool opaque) const {
@@ -1440,6 +1440,8 @@ void TabStrip::OnThemeChanged() {
   // available.
   if (MD::IsRefreshUi())
     SingleTabModeChanged();
+  else
+    FrameColorsChanged();
 }
 
 BrowserRootView::DropIndex TabStrip::GetDropIndex(
@@ -1507,7 +1509,7 @@ void TabStrip::Init() {
     drop_indicator_height = drop_image->height();
   }
 
-  UpdateOpacities();
+  UpdateContrastRatioValues();
 }
 
 void TabStrip::StartInsertTabAnimation(int model_index) {
@@ -2060,47 +2062,56 @@ void TabStrip::UpdateStackedLayoutFromMouseEvent(views::View* source,
   }
 }
 
-void TabStrip::UpdateOpacities() {
-  // There may be no controller in unit tests, and call to GetTabBackgroundColor
-  // below requires one, so bail early if it is absent.
+void TabStrip::UpdateContrastRatioValues() {
+  // There may be no controller in unit tests, and the call to
+  // GetTabBackgroundColor() below requires one, so bail early if it is absent.
   if (!controller_)
     return;
 
+  const SkColor active_tab_bg_color = GetTabBackgroundColor(TAB_ACTIVE, true);
+  const SkColor inactive_tab_bg_color =
+      GetTabBackgroundColor(TAB_INACTIVE, true);
+
   // The contrast ratio for the hover effect on standard-width tabs.
   // In the default Refresh color scheme, this corresponds to a hover
   // opacity of 0.4.
   constexpr float kDesiredContrastHoveredStandardWidthTab = 1.11f;
+  const SkAlpha hover_base_alpha_wide =
+      color_utils::GetBlendValueWithMinimumContrast(
+          inactive_tab_bg_color, active_tab_bg_color, inactive_tab_bg_color,
+          kDesiredContrastHoveredStandardWidthTab);
+  hover_opacity_min_ = hover_base_alpha_wide / 255.0f;
 
   // The contrast ratio for the hover effect on min-width tabs.
   // In the default Refresh color scheme, this corresponds to a hover
   // opacity of 0.65.
   constexpr float kDesiredContrastHoveredMinWidthTab = 1.19f;
+  const SkAlpha hover_base_alpha_narrow =
+      color_utils::GetBlendValueWithMinimumContrast(
+          inactive_tab_bg_color, active_tab_bg_color, inactive_tab_bg_color,
+          kDesiredContrastHoveredMinWidthTab);
+  hover_opacity_max_ = hover_base_alpha_narrow / 255.0f;
 
   // The contrast ratio for the radial gradient effect on hovered tabs.
   // In the default Refresh color scheme, this corresponds to a hover
   // opacity of 0.45.
   constexpr float kDesiredContrastRadialGradient = 1.13728f;
-
-  const SkColor active_tab_bg_color = GetTabBackgroundColor(TAB_ACTIVE, true);
-  const SkColor inactive_tab_bg_color =
-      GetTabBackgroundColor(TAB_INACTIVE, true);
-
-  const SkAlpha hover_base_alpha_wide =
-      color_utils::GetBlendValueWithMinimumContrast(
-          inactive_tab_bg_color, active_tab_bg_color, inactive_tab_bg_color,
-          kDesiredContrastHoveredStandardWidthTab);
-  const SkAlpha hover_base_alpha_narrow =
-      color_utils::GetBlendValueWithMinimumContrast(
-          inactive_tab_bg_color, active_tab_bg_color, inactive_tab_bg_color,
-          kDesiredContrastHoveredMinWidthTab);
   const SkAlpha radial_highlight_alpha =
       color_utils::GetBlendValueWithMinimumContrast(
           inactive_tab_bg_color, active_tab_bg_color, inactive_tab_bg_color,
           kDesiredContrastRadialGradient);
-
-  hover_opacity_min_ = hover_base_alpha_wide / 255.0f;
-  hover_opacity_max_ = hover_base_alpha_narrow / 255.0f;
   radial_highlight_opacity_ = radial_highlight_alpha / 255.0f;
+
+  // The contrast ratio for the separator between inactive tabs.
+  // In the default Refresh color scheme, this corresponds to a tab text opacity
+  // of 0.46.
+  const SkColor text_color = GetTabForegroundColor(TAB_INACTIVE);
+  constexpr float kTabSeparatorRatio = 1.84f;
+  const SkAlpha separator_alpha = color_utils::GetBlendValueWithMinimumContrast(
+      inactive_tab_bg_color, text_color, inactive_tab_bg_color,
+      kTabSeparatorRatio);
+  separator_color_ = color_utils::AlphaBlend(text_color, inactive_tab_bg_color,
+                                             separator_alpha);
 }
 
 void TabStrip::ResizeLayoutTabs() {

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

@@ -20,6 +20,7 @@
 #include "chrome/browser/ui/views/tabs/tab_controller.h"
 #include "chrome/browser/ui/views/tabs/tab_strip.h"
 #include "ui/gfx/animation/animation_container.h"
+#include "ui/gfx/color_palette.h"
 #include "ui/gfx/geometry/point.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/views/animation/bounds_animator.h"
@@ -456,8 +457,8 @@ class TabStrip : public views::View,
   void UpdateStackedLayoutFromMouseEvent(views::View* source,
                                          const ui::MouseEvent& event);
 
-  // Computes and stores tab hover opacities derived from contrast ratios.
-  void UpdateOpacities();
+  // Computes and stores values derived from contrast ratios.
+  void UpdateContrastRatioValues();
 
   // -- Tab Resize Layout -----------------------------------------------------
 
@@ -690,6 +691,8 @@ class TabStrip : public views::View,
   float hover_opacity_max_ = 1.0f;
   float radial_highlight_opacity_ = 1.0f;
 
+  SkColor separator_color_ = gfx::kPlaceholderColor;
+
   DISALLOW_COPY_AND_ASSIGN(TabStrip);
 };
 

chrome/browser/ui/views/tabs/tab_strip_controller.h

@@ -131,9 +131,6 @@ class TabStripController {
   // state of the window.
   virtual SkColor GetToolbarTopSeparatorColor() const = 0;
 
-  // Under Refresh, returns the color of the separator between the tabs.
-  virtual SkColor GetTabSeparatorColor() const = 0;
-
   // Returns the tab background color based on both the |state| of the tab and
   // the activation state of the window.  If |opaque| is true, the resulting
   // color after drawing the tab background on the frame will be returned.