Add RippleAttributes in AshColorProvider.

Add RippleAttributes and corresponding get function in AshColorProvider
for ripple.

Bug: 972162
Change-Id: I49ffb4cb2a01600f210a57f2e7adb3bf21088513
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1686790
Commit-Queue: Min Chen <minch@chromium.org>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#680156}

ash/style/ash_color_provider.cc

@@ -9,11 +9,16 @@
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
 #include "ui/gfx/color_palette.h"
+#include "ui/gfx/color_utils.h"
 
 namespace ash {
 
 namespace {
 
+// Opacity of the light/dark ink ripple.
+constexpr float kLightInkRippleOpacity = 0.08f;
+constexpr float kDarkInkRippleOpacity = 0.06f;
+
 // Gets the color mode value from feature flag "--ash-color-mode".
 AshColorProvider::AshColorMode GetColorModeFromCommandLine() {
   const base::CommandLine* cl = base::CommandLine::ForCurrentProcess();
@@ -98,6 +103,15 @@ SkColor AshColorProvider::GetControlsLayerColor(ControlsLayerType type) const {
   return SelectColorOnMode(light_color, dark_color);
 }
 
+AshColorProvider::RippleAttributes AshColorProvider::GetRippleAttributes(
+    SkColor bg_color) const {
+  const SkColor base_color = color_utils::GetColorWithMaxContrast(bg_color);
+  const float opacity = color_utils::IsDark(base_color)
+                            ? kDarkInkRippleOpacity
+                            : kLightInkRippleOpacity;
+  return RippleAttributes(base_color, opacity, opacity);
+}
+
 SkColor AshColorProvider::SelectColorOnMode(SkColor light_color,
                                             SkColor dark_color) const {
   if (color_mode_ == AshColorMode::kLight)

ash/style/ash_color_provider.h

@@ -62,6 +62,20 @@ class AshColorProvider {
     kFocusRing,
   };
 
+  // Attributes of ripple, includes the base color, opacity of inkdrop and
+  // highlight.
+  struct RippleAttributes {
+    RippleAttributes(SkColor color,
+                     float opacity_of_inkdrop,
+                     float opacity_of_highlight)
+        : base_color(color),
+          inkdrop_opacity(opacity_of_inkdrop),
+          highlight_opacity(opacity_of_highlight) {}
+    const SkColor base_color;
+    const float inkdrop_opacity;
+    const float highlight_opacity;
+  };
+
   AshColorProvider();
   ~AshColorProvider();
 
@@ -70,6 +84,10 @@ class AshColorProvider {
   SkColor GetBaseLayerColor(BaseLayerType type) const;
   SkColor GetControlsLayerColor(ControlsLayerType type) const;
 
+  // Gets the attributes of ripple on |bg_color|. |bg_color| is the background
+  // color of the UI element that wants to show inkdrop.
+  RippleAttributes GetRippleAttributes(SkColor bg_color) const;
+
   AshColorMode color_mode() const { return color_mode_; }
 
  private: