[Snowflake] Update button widget to match v2 ripple color

+ Add support for ripple color on borderless button
+ Refactor out background drawable logic to another class

Bug: 849126, 856244
Change-Id: I5960714129110bea0b9d284779f71592d90e4a36
Reviewed-on: https://chromium-review.googlesource.com/c/1293172Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Becky Zhou <huayinz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#601756}

chrome/android/java/res/color/chip_background_color.xml

@@ -5,7 +5,7 @@
 -->
 
 <selector xmlns:android="http://schemas.android.com/apk/res/android">
-    <item android:alpha="@dimen/chip_background_disabled_alpha"
+    <item android:alpha="@dimen/default_disabled_alpha"
         android:color="@color/modern_grey_100"
         android:state_enabled="false" />
     <item android:alpha="@dimen/chip_background_selected_focused_alpha"
@@ -15,7 +15,7 @@
     <item android:alpha="@dimen/chip_background_selected_alpha"
         android:color="@color/modern_blue_600"
         android:state_selected="true" />
-    <item android:alpha="@dimen/chip_background_focused_alpha"
+    <item android:alpha="@dimen/default_focused_alpha"
         android:color="@color/modern_grey_800"
         android:state_focused="true" />
     <item android:color="@android:color/white" />

chrome/android/java/res/layout/history_clear_browsing_data_header.xml

@@ -9,21 +9,15 @@
     android:orientation="vertical"
     android:paddingBottom="8dp" >
 
-        <Button
+        <org.chromium.ui.widget.ButtonCompat
             android:id="@+id/clear_browsing_data_button"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:layout_gravity="top"
-            style="@style/ButtonCompatBorderless"
-            android:paddingTop="16dp"
-            android:paddingBottom="16dp"
-            android:paddingStart="@dimen/list_item_default_margin"
-            android:paddingEnd="@dimen/list_item_default_margin"
+            android:padding="@dimen/list_item_default_margin"
             android:gravity="center_vertical|start"
             android:text="@string/open_clear_browsing_data_dialog_button"
-            android:textAllCaps="true"
-            android:textColor="@color/blue_when_enabled"
-            android:textSize="@dimen/text_size_medium" />
+            style="@style/TextButton" />
 
         <View style="@style/HorizontalDivider" />
 

chrome/android/java/res/layout/personalized_signin_promo_view_body.xml

@@ -21,7 +21,7 @@
 
     <org.chromium.ui.widget.ButtonCompat
         android:id="@+id/signin_promo_signin_button"
-        style="@style/SigninButtonCompat"
+        style="@style/FilledButton.Flat"
         android:layout_width="match_parent"
         android:layout_height="36dp"
         android:layout_marginBottom="6dp"

chrome/android/java/res/values-v17/styles.xml

@@ -600,11 +600,6 @@
         <item name="android:textAppearance">@style/BlackBody</item>
         <item name="android:layout_gravity">start</item>
     </style>
-    <style name="SigninButtonCompat">
-        <item name="android:textAppearance">@style/WhiteButtonText</item>
-        <item name="buttonColor">@color/light_active_color</item>
-        <item name="buttonRaised">false</item>
-    </style>
     <style name="SigninButtonBorderlessRegular">
         <item name="android:background">?android:attr/selectableItemBackground</item>
         <item name="android:paddingStart">0dp</item>

chrome/android/java/res/values/dimens.xml

@@ -535,8 +535,6 @@
     <dimen name="chip_icon_padding">8dp</dimen>
     <dimen name="chip_list_inter_chip_padding">2.5dp</dimen>
     <dimen name="chip_list_side_padding">16dp</dimen>
-    <item name="chip_background_disabled_alpha" format="float" type="dimen">0.38</item>
-    <item name="chip_background_focused_alpha" format="float" type="dimen">0.06</item>
     <item name="chip_background_selected_focused_alpha" format="float" type="dimen">0.12</item>
     <item name="chip_background_selected_alpha" format="float" type="dimen">0.06</item>
 

chrome/android/java/src/org/chromium/chrome/browser/infobar/AppBannerInfoBarAndroid.java

@@ -7,11 +7,11 @@ package org.chromium.chrome.browser.infobar;
 import android.content.Context;
 import android.graphics.Bitmap;
 import android.support.v4.view.ViewCompat;
+import android.support.v7.content.res.AppCompatResources;
 import android.view.View;
 import android.widget.Button;
 import android.widget.ImageView;
 
-import org.chromium.base.ApiCompatibilityUtils;
 import org.chromium.base.ContextUtils;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.chrome.R;
@@ -72,8 +72,8 @@ public class AppBannerInfoBarAndroid extends ConfirmInfoBar implements View.OnCl
         Context context = getContext();
         if (mAppData != null) {
             // Native app.
-            layout.getPrimaryButton().setButtonColor(ApiCompatibilityUtils.getColor(
-                    context.getResources(), R.color.app_banner_install_button_bg));
+            layout.getPrimaryButton().setButtonColor(AppCompatResources.getColorStateList(
+                    context, R.color.app_banner_install_button_bg));
             mMessageLayout.addRatingBar(mAppData.rating());
             mMessageLayout.setContentDescription(context.getString(
                     R.string.app_banner_view_native_app_accessibility, mAppTitle,

chrome/android/java/src/org/chromium/chrome/browser/infobar/InstantAppsInfoBar.java

@@ -4,9 +4,9 @@
 
 package org.chromium.chrome.browser.infobar;
 
+import android.support.v7.content.res.AppCompatResources;
 import android.widget.ImageView;
 
-import org.chromium.base.ApiCompatibilityUtils;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.instantapps.InstantAppsBannerData;
@@ -33,9 +33,8 @@ public class InstantAppsInfoBar extends ConfirmInfoBar {
         layout.setMessage(mData.getAppName());
         layout.getMessageLayout().addDescription(
                 UrlFormatter.formatUrlForSecurityDisplayOmitScheme(mData.getUrl()));
-        layout.getPrimaryButton()
-                .setButtonColor(ApiCompatibilityUtils.getColor(getContext().getResources(),
-                        R.color.app_banner_install_button_bg));
+        layout.getPrimaryButton().setButtonColor(AppCompatResources.getColorStateList(
+                getContext(), R.color.app_banner_install_button_bg));
     }
 
     @Override

chrome/android/java/src/org/chromium/chrome/browser/widget/DualControlLayout.java

@@ -64,18 +64,15 @@ public final class DualControlLayout extends ViewGroup {
      */
     public static Button createButtonForLayout(
             Context context, boolean isPrimary, String text, OnClickListener listener) {
-        int buttonColor =
-                ApiCompatibilityUtils.getColor(context.getResources(), R.color.light_active_color);
-
         if (isPrimary) {
-            ButtonCompat primaryButton = new ButtonCompat(context, buttonColor, false);
+            ButtonCompat primaryButton =
+                    new ButtonCompat(context, R.style.FilledButtonThemeOverlay_Flat);
             primaryButton.setId(R.id.button_primary);
             primaryButton.setOnClickListener(listener);
             primaryButton.setText(text);
-            ApiCompatibilityUtils.setTextAppearance(primaryButton, R.style.WhiteButtonText);
             return primaryButton;
         } else {
-            Button secondaryButton = ButtonCompat.createBorderlessButton(context);
+            Button secondaryButton = new ButtonCompat(context, R.style.TextButtonThemeOverlay);
             secondaryButton.setId(R.id.button_secondary);
             secondaryButton.setOnClickListener(listener);
             secondaryButton.setText(text);

ui/android/BUILD.gn

@@ -313,6 +313,7 @@ android_library("ui_full_java") {
     "java/src/org/chromium/ui/widget/ChromeBulletSpan.java",
     "java/src/org/chromium/ui/widget/OptimizedFrameLayout.java",
     "java/src/org/chromium/ui/widget/RectProvider.java",
+    "java/src/org/chromium/ui/widget/RippleBackgroundHelper.java",
     "java/src/org/chromium/ui/widget/RoundedCornerImageView.java",
     "java/src/org/chromium/ui/widget/TextViewWithClickableSpans.java",
     "java/src/org/chromium/ui/widget/TextViewWithLeading.java",

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

@@ -4,6 +4,7 @@
      found in the LICENSE file.
 -->
 <selector xmlns:android="http://schemas.android.com/apk/res/android">
-    <item android:state_enabled="false" android:color="@color/black_alpha_38" />
+    <item android:alpha="@dimen/default_disabled_alpha"
+        android:color="@color/modern_grey_800" android:state_enabled="false" />
     <item android:color="@color/default_text_color_link"/>
 </selector>

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

@@ -4,7 +4,7 @@
      found in the LICENSE file.
 -->
 <selector xmlns:android="http://schemas.android.com/apk/res/android">
-    <item android:alpha="@dimen/disabled_text_alpha" android:color="@color/default_text_color"
-        android:state_enabled="false"/>
+    <item android:alpha="@dimen/default_disabled_alpha"
+        android:color="@color/default_text_color" android:state_enabled="false"/>
     <item android:color="@color/default_text_color" />
 </selector>
\ No newline at end of file

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

@@ -4,7 +4,7 @@
      found in the LICENSE file.
 -->
 <selector xmlns:android="http://schemas.android.com/apk/res/android">
-    <item android:alpha="@dimen/disabled_text_alpha"
+    <item android:alpha="@dimen/default_disabled_alpha"
         android:color="@color/default_text_color_secondary" android:state_enabled="false"/>
     <item android:color="@color/default_text_color_secondary" />
 </selector>
\ No newline at end of file

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

+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright 2018 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. -->
+
+<selector
+    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="@android:color/transparent" />
+</selector>
\ No newline at end of file

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

+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright 2018 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. -->
+
+<selector
+    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="@color/modern_blue_600" android:state_pressed="true"/>
+    <item android:alpha="@dimen/default_focused_hovered_alpha"
+        android:color="@color/modern_blue_600" android:state_focused="true" android:state_hovered="true"/>
+    <item android:alpha="@dimen/default_focused_alpha"
+        android:color="@color/modern_blue_600" android:state_focused="true"/>
+    <item android:alpha="@dimen/default_hovered_alpha"
+        android:color="@color/modern_blue_600" android:state_hovered="true"/>
+    <item android:color="@android:color/transparent" />
+</selector>
\ No newline at end of file

ui/android/java/res/drawable/button_compat_shape.xml

@@ -5,5 +5,5 @@
 
 <shape xmlns:android="http://schemas.android.com/apk/res/android">
     <solid android:color="#fff" />
-    <corners android:radius="2dp" />
+    <corners android:radius="@dimen/button_compat_corner_radius" />
 </shape>

ui/android/java/res/values-v17/styles.xml

@@ -12,12 +12,16 @@
     </style>
 
     <!-- Buttons -->
-    <style name="ButtonCompatOverlay">
-        <item name="android:buttonStyle">@style/ButtonCompat</item>
+    <style name="FilledButtonThemeOverlay">
+        <item name="android:buttonStyle">@style/FilledButton</item>
     </style>
-    <style name="ButtonCompatBorderlessOverlay">
-        <item name="android:buttonStyle">@style/ButtonCompatBorderless</item>
+    <style name="FilledButtonThemeOverlay.Flat" tools:ignore="UnusedResources">
+        <item name="android:buttonStyle">@style/FilledButton.Flat</item>
     </style>
+    <style name="TextButtonThemeOverlay" tools:ignore="UnusedResources">
+        <item name="android:buttonStyle">@style/TextButton</item>
+    </style>
+
     <style name="ButtonCompatBase">
         <item name="android:minWidth">88dp</item>
         <item name="android:minHeight">36dp</item>
@@ -29,10 +33,27 @@
         <item name="android:clickable">true</item>
         <item name="android:gravity">center_vertical|center_horizontal</item>
     </style>
-    <style name="ButtonCompat" parent="ButtonCompatBase">
+    <style name="FilledButton" parent="ButtonCompatBase" tools:ignore="UnusedResources">
+        <item name="android:textAppearance">@style/WhiteButtonText</item>
+        <item name="buttonColor">@color/blue_when_enabled</item>
+        <item name="rippleColor">@color/filled_button_ripple_color</item>
+        <item name="buttonRaised">true</item>
+    </style>
+    <style name="FilledButton.Flat" tools:ignore="UnusedResources">
+        <item name="buttonRaised">false</item>
+    </style>
+    <style name="TextButton" parent="ButtonCompatBase" tools:ignore="UnusedResources">
+        <item name="android:textAppearance">@style/BlueButtonText2</item>
+        <item name="buttonColor">@android:color/transparent</item>
+        <item name="rippleColor">@color/text_button_ripple_color</item>
+        <item name="buttonRaised">false</item>
+    </style>
+
+    <!-- TODO(huayinz): Remove these once button unification is done. -->
+    <style name="ButtonCompat" parent="ButtonCompatBase" tools:ignore="UnusedResources">
         <item name="android:background">@drawable/button_compat_shape</item>
     </style>
-    <style name="ButtonCompatBorderless" parent="ButtonCompat">
+    <style name="ButtonCompatBorderless" parent="ButtonCompat" tools:ignore="UnusedResources">
         <item name="android:background">?android:attr/selectableItemBackground</item>
     </style>
 

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

@@ -13,19 +13,24 @@
             <enum name="apart" value="2" />
         </attr>
     </declare-styleable>
+
     <declare-styleable name="ButtonCompat">
-        <attr name="buttonColor" format="reference|color"/>
+        <attr name="buttonColor" format="color"/>
+        <attr name="rippleColor" format="color"/>
         <attr name="buttonRaised" format="boolean"/>
     </declare-styleable>
+
     <declare-styleable name="TextViewWithLeading">
         <attr name="leading" format="reference|dimension"/>
     </declare-styleable>
+
     <declare-styleable name="AsyncViewStub">
         <!-- Supply an identifier for the layout resource to inflate when the AsyncViewStub
              becomes visible or when forced to do so. The layout resource must be a
              valid reference to a layout. -->
         <attr name="layout" format="reference" />
     </declare-styleable>
+
     <declare-styleable name="RoundedCornerImageView">
         <attr name="cornerRadiusTopStart" format="dimension" />
         <attr name="cornerRadiusTopEnd" format="dimension" />

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

@@ -12,7 +12,11 @@
     <dimen name="text_size_small">12sp</dimen>
 
     <!-- Common alpha values -->
-    <item name="disabled_text_alpha" format="float" type="dimen">0.38</item>
+    <item name="default_disabled_alpha" format="float" type="dimen">0.38</item>
+    <item name="default_pressed_alpha" format="float" type="dimen">0.10</item>
+    <item name="default_focused_hovered_alpha" format="float" type="dimen">0.10</item>
+    <item name="default_focused_alpha" format="float" type="dimen">0.06</item>
+    <item name="default_hovered_alpha" format="float" type="dimen">0.04</item>
 
     <dimen name="dropdown_item_height">50dp</dimen>
     <dimen name="dropdown_item_divider_height">1px</dimen>

ui/android/java/src/org/chromium/ui/widget/ButtonCompat.java

@@ -6,17 +6,14 @@ package org.chromium.ui.widget;
 
 import android.animation.AnimatorInflater;
 import android.animation.StateListAnimator;
-import android.annotation.TargetApi;
 import android.content.Context;
 import android.content.res.ColorStateList;
 import android.content.res.TypedArray;
-import android.graphics.Color;
-import android.graphics.drawable.GradientDrawable;
-import android.graphics.drawable.RippleDrawable;
 import android.os.Build;
+import android.support.annotation.StyleRes;
+import android.support.v7.widget.AppCompatButton;
 import android.util.AttributeSet;
 import android.view.ContextThemeWrapper;
-import android.widget.Button;
 
 import org.chromium.ui.R;
 
@@ -26,7 +23,7 @@ import org.chromium.ui.R;
  *
  * Create a button in Java:
  *
- *   new ButtonCompat(context, Color.RED);
+ *   new ButtonCompat(context, R.style.TextButtonThemeOverlay);
  *
  * Create a button in XML:
  *
@@ -34,68 +31,52 @@ import org.chromium.ui.R;
  *       android:layout_width="wrap_content"
  *       android:layout_height="wrap_content"
  *       android:text="Click me"
- *       chrome:buttonColor="#f00" />
+ *       style="@style/TextButton" />
  *
  * Note: To ensure the button's shadow is fully visible, you may need to set
  * android:clipToPadding="false" on the button's parent view.
  */
-@TargetApi(Build.VERSION_CODES.LOLLIPOP)
-public class ButtonCompat extends Button {
-
-    private static final float PRE_L_PRESSED_BRIGHTNESS = 0.85f;
-    private static final int DISABLED_COLOR = 0x424F4F4F;
-
-    private final int mCornerRadius;
-    private int mColor;
+public class ButtonCompat extends AppCompatButton {
+    private RippleBackgroundHelper mRippleBackgroundHelper;
 
     /**
-     * Returns a new borderless material-style button.
+     * Constructor for programmatically creating a {@link ButtonCompat}.
+     * @param context The {@link Context} for this class.
+     * @param themeOverlay The style resource id that sets android:buttonStyle to specify the button
+     *                     style.
      */
-    public static Button createBorderlessButton(Context context) {
-        return new Button(new ContextThemeWrapper(context, R.style.ButtonCompatBorderlessOverlay));
+    public ButtonCompat(Context context, @StyleRes int themeOverlay) {
+        this(context, null, themeOverlay);
     }
 
     /**
-     * Constructs a button with the given buttonColor as its background. The button is raised if
-     * buttonRaised is true.
-     */
-    public ButtonCompat(Context context, int buttonColor, boolean buttonRaised) {
-        this(context, buttonColor, buttonRaised, null);
-    }
-
-    /**
-     * Constructor for inflating from XML.
+     * Constructor for inflating from XMLs.
      */
     public ButtonCompat(Context context, AttributeSet attrs) {
-        this(context, getColorFromAttributeSet(context, attrs),
-                getRaisedStatusFromAttributeSet(context, attrs), attrs);
+        this(context, attrs, R.style.FilledButtonThemeOverlay);
     }
 
-    private ButtonCompat(
-            Context context, int buttonColor, boolean buttonRaised, AttributeSet attrs) {
-        // To apply the ButtonCompat style to this view, use a ContextThemeWrapper to overlay the
-        // ButtonCompatThemeOverlay, which simply sets the buttonStyle to @style/ButtonCompat.
-        super(new ContextThemeWrapper(context, R.style.ButtonCompatOverlay), attrs);
+    private ButtonCompat(Context context, AttributeSet attrs, @StyleRes int themeOverlay) {
+        super(new ContextThemeWrapper(context, themeOverlay), attrs, android.R.attr.buttonStyle);
+
+        TypedArray a = getContext().obtainStyledAttributes(
+                attrs, R.styleable.ButtonCompat, android.R.attr.buttonStyle, 0);
+        int buttonColorId =
+                a.getResourceId(R.styleable.ButtonCompat_buttonColor, R.color.blue_when_enabled);
+        int rippleColorId = a.getResourceId(
+                R.styleable.ButtonCompat_rippleColor, R.color.filled_button_ripple_color);
+        boolean buttonRaised = a.getBoolean(R.styleable.ButtonCompat_buttonRaised, true);
+        a.recycle();
 
-        mCornerRadius =
-                context.getResources().getDimensionPixelSize(R.dimen.button_compat_corner_radius);
-        getBackground().mutate();
-        setButtonColor(buttonColor);
+        mRippleBackgroundHelper = new RippleBackgroundHelper(this, buttonColorId, rippleColorId);
         setRaised(buttonRaised);
     }
 
     /**
      * Sets the background color of the button.
      */
-    public void setButtonColor(int color) {
-        if (color == mColor) return;
-        mColor = color;
-
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
-            updateButtonBackgroundL();
-        } else {
-            updateButtonBackgroundPreL();
-        }
+    public void setButtonColor(ColorStateList buttonColorList) {
+        mRippleBackgroundHelper.setBackgroundColor(buttonColorList);
     }
 
     /**
@@ -134,59 +115,8 @@ public class ButtonCompat extends Button {
     @Override
     protected void drawableStateChanged() {
         super.drawableStateChanged();
-        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
-            updateButtonBackgroundPreL();
+        if (mRippleBackgroundHelper != null) {
+            mRippleBackgroundHelper.onDrawableStateChanged();
         }
     }
-
-    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
-    private void updateButtonBackgroundL() {
-        ColorStateList csl = new ColorStateList(
-                new int[][] { { -android.R.attr.state_enabled }, {} },
-                new int[] { DISABLED_COLOR, mColor });
-        GradientDrawable shape = (GradientDrawable)
-                ((RippleDrawable) getBackground()).getDrawable(0);
-        shape.mutate();
-        shape.setCornerRadius(mCornerRadius);
-        shape.setColor(csl);
-    }
-
-    private void updateButtonBackgroundPreL() {
-        GradientDrawable background = (GradientDrawable) getBackground();
-        background.setCornerRadius(mCornerRadius);
-        background.setColor(getBackgroundColorPreL());
-    }
-
-    private int getBackgroundColorPreL() {
-        for (int state : getDrawableState()) {
-            if (state == android.R.attr.state_pressed
-                    || state == android.R.attr.state_focused
-                    || state == android.R.attr.state_selected) {
-                return Color.rgb(
-                        Math.round(Color.red(mColor) * PRE_L_PRESSED_BRIGHTNESS),
-                        Math.round(Color.green(mColor) * PRE_L_PRESSED_BRIGHTNESS),
-                        Math.round(Color.blue(mColor) * PRE_L_PRESSED_BRIGHTNESS));
-            }
-        }
-        for (int state : getDrawableState()) {
-            if (state == android.R.attr.state_enabled) {
-                return mColor;
-            }
-        }
-        return DISABLED_COLOR;
-    }
-
-    private static int getColorFromAttributeSet(Context context, AttributeSet attrs) {
-        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ButtonCompat, 0, 0);
-        int color = a.getColor(R.styleable.ButtonCompat_buttonColor, Color.WHITE);
-        a.recycle();
-        return color;
-    }
-
-    private static boolean getRaisedStatusFromAttributeSet(Context context, AttributeSet attrs) {
-        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ButtonCompat, 0, 0);
-        boolean raised = a.getBoolean(R.styleable.ButtonCompat_buttonRaised, true);
-        a.recycle();
-        return raised;
-    }
 }

ui/android/java/src/org/chromium/ui/widget/RippleBackgroundHelper.java

+// Copyright 2018 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.
+
+package org.chromium.ui.widget;
+
+import android.annotation.TargetApi;
+import android.content.res.ColorStateList;
+import android.graphics.Color;
+import android.graphics.drawable.Drawable;
+import android.graphics.drawable.GradientDrawable;
+import android.graphics.drawable.LayerDrawable;
+import android.graphics.drawable.RippleDrawable;
+import android.os.Build;
+import android.support.annotation.ColorInt;
+import android.support.annotation.ColorRes;
+import android.support.annotation.Nullable;
+import android.support.v4.graphics.ColorUtils;
+import android.support.v4.graphics.drawable.DrawableCompat;
+import android.support.v7.content.res.AppCompatResources;
+import android.util.StateSet;
+import android.view.View;
+
+import org.chromium.ui.R;
+
+/**
+ * A helper class to create and maintain a background drawable with customized background color,
+ * ripple color, and corner radius.
+ */
+class RippleBackgroundHelper {
+    private static final int[] STATE_SET_PRESSED = {android.R.attr.state_pressed};
+    private static final int[] STATE_SET_SELECTED = {android.R.attr.state_selected};
+    private static final int[] STATE_SET_SELECTED_PRESSED = {
+            android.R.attr.state_selected, android.R.attr.state_pressed};
+
+    private final View mView;
+
+    private @Nullable ColorStateList mBackgroundColorList;
+
+    private GradientDrawable mBackgroundGradient;
+
+    // Used for applying tint on pre-L versions.
+    private Drawable mBackgroundDrawablePreL;
+    private Drawable mRippleDrawablePreL;
+
+    /**
+     * @param view The {@link View} on which background will be applied.
+     * @param backgroundColorResId The resource id of the background color.
+     * @param rippleColorResId The resource id of the ripple color.
+     */
+    RippleBackgroundHelper(
+            View view, @ColorRes int backgroundColorResId, @ColorRes int rippleColorResId) {
+        mView = view;
+        ColorStateList rippleColorList =
+                AppCompatResources.getColorStateList(view.getContext(), rippleColorResId);
+
+        int cornerRadius =
+                view.getResources().getDimensionPixelSize(R.dimen.button_compat_corner_radius);
+        ColorStateList backgroundColorList =
+                AppCompatResources.getColorStateList(view.getContext(), backgroundColorResId);
+
+        mBackgroundGradient = new GradientDrawable();
+        mBackgroundGradient.setCornerRadius(cornerRadius);
+
+        Drawable wrappedDrawable;
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
+            mBackgroundDrawablePreL = DrawableCompat.wrap(mBackgroundGradient);
+            GradientDrawable rippleGradient = new GradientDrawable();
+            rippleGradient.setCornerRadius(cornerRadius);
+            mRippleDrawablePreL = DrawableCompat.wrap(rippleGradient);
+            DrawableCompat.setTintList(mRippleDrawablePreL, rippleColorList);
+            wrappedDrawable = new LayerDrawable(
+                    new Drawable[] {mBackgroundDrawablePreL, mRippleDrawablePreL});
+        } else {
+            GradientDrawable mask = new GradientDrawable();
+            mask.setCornerRadius(cornerRadius);
+            mask.setColor(Color.WHITE);
+            wrappedDrawable = new RippleDrawable(
+                    convertToRippleDrawableColorList(rippleColorList), mBackgroundGradient, mask);
+        }
+
+        int paddingLeft = mView.getPaddingLeft();
+        int paddingTop = mView.getPaddingTop();
+        int paddingRight = mView.getPaddingRight();
+        int paddingBottom = mView.getPaddingBottom();
+        mView.setBackground(wrappedDrawable);
+        setBackgroundColor(backgroundColorList);
+
+        // On KitKat, setting the background on the view can cause padding reset. Save the padding
+        // and re-apply after background is set.
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
+            mView.setPadding(paddingLeft, paddingTop, paddingRight, paddingBottom);
+        }
+    }
+
+    /**
+     * @param color The {@link ColorStateList} to be set as the background color on the background
+     *              drawable.
+     */
+    void setBackgroundColor(ColorStateList color) {
+        if (color == mBackgroundColorList) return;
+
+        mBackgroundColorList = color;
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
+            DrawableCompat.setTintList(mBackgroundDrawablePreL, color);
+        } else {
+            mBackgroundGradient.setColor(color);
+        }
+    }
+
+    /**
+     * Called from the view when drawable state is changed to update the state of the background
+     * color and the ripple color for pre-L versions.
+     */
+    void onDrawableStateChanged() {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) return;
+
+        int[] state = mView.getDrawableState();
+        mBackgroundDrawablePreL.setState(state);
+        mRippleDrawablePreL.setState(state);
+    }
+
+    /**
+     * @return The color under the specified states in the specified {@link ColorStateList}.
+     */
+    private static @ColorInt int getColorForState(ColorStateList colorStateList, int[] states) {
+        return colorStateList.getColorForState(states, colorStateList.getDefaultColor());
+    }
+
+    /**
+     * Adjusts the opacity of the ripple color since {@link RippleDrawable} uses about 50% opacity
+     * of color for ripple effect.
+     */
+    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
+    private @ColorInt static int doubleAlpha(@ColorInt int color) {
+        int alpha = Math.min(Color.alpha(color) * 2, 255);
+        return ColorUtils.setAlphaComponent(color, alpha);
+    }
+
+    /**
+     * Converts the specified {@link ColorStateList} to one that can be applied to a
+     * {@link RippleDrawable}.
+     */
+    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
+    private static ColorStateList convertToRippleDrawableColorList(ColorStateList colorStateList) {
+        return new ColorStateList(new int[][] {STATE_SET_SELECTED, StateSet.NOTHING},
+                new int[] {
+                        doubleAlpha(getColorForState(colorStateList, STATE_SET_SELECTED_PRESSED)),
+                        doubleAlpha(getColorForState(colorStateList, STATE_SET_PRESSED))});
+    }
+}