Fix FilledButton state colors

Update FilledButton styles to adhere to the design spec. See
go/clankdictionary and go/clankcolors.

This change improves button accessibility by increasing the contrast
ratio.

Bug: 994365
Change-Id: I9fd61bdcde706c5ad6d27093a618807228ff0025
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1910868Reviewed-by: Matthew Jones <mdjones@chromium.org>
Commit-Queue: Natalie Chouinard <chouinard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#714687}

ui/android/java/res/color/filled_button_ripple_color.xml

@@ -7,13 +7,8 @@
     xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     tools:ignore="UnusedResources">
-    <item android:alpha="@dimen/default_pressed_alpha"
-        android:color="@android:color/white" android:state_pressed="true"/>
-    <item android:alpha="@dimen/default_focused_hovered_alpha"
-        android:color="@android:color/white" android:state_focused="true" android:state_hovered="true"/>
-    <item android:alpha="@dimen/default_focused_alpha"
-        android:color="@android:color/white" android:state_focused="true"/>
-    <item android:alpha="@dimen/default_hovered_alpha"
-        android:color="@android:color/white" android:state_hovered="true"/>
+    <item android:color="@color/white_alpha_32" android:state_pressed="true"/>
+    <item android:color="@color/white_alpha_24" android:state_focused="true"/>
+    <item android:color="@color/white_alpha_8" android:state_hovered="true"/>
     <item android:color="@android:color/transparent" />
 </selector>
\ No newline at end of file

ui/android/java/res/values/color_palette.xml

@@ -28,9 +28,12 @@
 
     <color name="black_alpha_38" tools:ignore="UnusedResources">#61000000</color>
 
+    <color name="white_alpha_8" tools:ignore="UnusedResources">#14FFFFFF</color>
     <color name="white_alpha_10" tools:ignore="UnusedResources">#1AFFFFFF</color>
     <color name="white_alpha_12" tools:ignore="UnusedResources">#1FFFFFFF</color>
     <color name="white_alpha_20" tools:ignore="UnusedResources">#33FFFFFF</color>
+    <color name="white_alpha_24" tools:ignore="UnusedResources">#3DFFFFFF</color>
+    <color name="white_alpha_32" tools:ignore="UnusedResources">#51FFFFFF</color>
     <color name="white_alpha_38" tools:ignore="UnusedResources">#61FFFFFF</color>
     <color name="white_alpha_50" tools:ignore="UnusedResources">#80FFFFFF</color>
     <color name="white_alpha_70">#B3FFFFFF</color>