Upstream oodles of Chrome for Android code into Chromium.

chrome/android/java_staging/src/org/chromium/chrome/browser/widget/FadingShadowView.java

+// Copyright 2015 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.chrome.browser.widget;
+
+import android.content.Context;
+import android.graphics.Canvas;
+import android.util.AttributeSet;
+import android.view.View;
+
+/**
+ * A class that encapsulates {@link FadingShadow} as a self-contained view.
+ */
+public class FadingShadowView extends View {
+    private FadingShadow mFadingShadow;
+    private int mPosition;
+    private float mStrength;
+
+    /**
+     * Constructor for inflating from XML.
+     */
+    public FadingShadowView(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    /**
+     * Sets shadow color and position, please refer to the below function. Note that this function
+     * must be called before using this class.
+     * @see FadingShadow#drawShadow(View, Canvas, int, float, float)
+     */
+    public void init(int shadowColor, int position) {
+        mFadingShadow = new FadingShadow(shadowColor);
+        mPosition = position;
+        postInvalidateOnAnimation();
+    }
+
+    /**
+     * Sets the shadow strength. Please refer to the below function's shadowStrength argument.
+     * @see FadingShadow#drawShadow(View, Canvas, int, float, float)
+     */
+    public void setStrength(float strength) {
+        if (mStrength != strength) {
+            mStrength = strength;
+            postInvalidateOnAnimation();
+        }
+    }
+
+    /**
+     * Gets the shadow strength. Please refer to the below function's shadowStrength argument.
+     * @see FadingShadow#drawShadow(View, Canvas, int, float, float)
+     */
+    public float getStrength() {
+        return mStrength;
+    }
+
+    @Override
+    protected void onDraw(Canvas canvas) {
+        super.onDraw(canvas);
+        if (mFadingShadow != null) {
+            mFadingShadow.drawShadow(this, canvas, mPosition, getHeight(), mStrength);
+        }
+    }
+}