Add support for highlighting menu items

chrome/android/java/src/org/chromium/chrome/browser/appmenu/IconHighlightDrawable.java

Index: chrome/android/java/src/org/chromium/chrome/browser/appmenu/IconHighlightDrawable.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/appmenu/IconHighlightDrawable.java b/chrome/android/java/src/org/chromium/chrome/browser/appmenu/IconHighlightDrawable.java
new file mode 100644
index 0000000000000000000000000000000000000000..366f8b2b581ca1dbc9915cb48fd15b7ca092ea56
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/appmenu/IconHighlightDrawable.java
@@ -0,0 +1,115 @@
+// Copyright 2017 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.appmenu;
+
+import android.animation.Animator;
+import android.animation.AnimatorListenerAdapter;
+import android.animation.AnimatorSet;
+import android.animation.ObjectAnimator;
+import android.graphics.Canvas;
+import android.graphics.Rect;
+import android.graphics.drawable.Drawable;
+import android.graphics.drawable.ShapeDrawable;
+import android.graphics.drawable.shapes.OvalShape;
+import android.support.annotation.ColorRes;
+import android.support.v4.view.animation.PathInterpolatorCompat;
+
+/** A {@link Drawable} that draws a circular pulsing dot. */
+public class IconHighlightDrawable extends ShapeDrawable {
+    private final Rect mCacheRect = new Rect();
+    private final Rect mMargin = new Rect();
+    private float mScale;
+
+    /**
+     * Creates a new {@link IconHighlightDrawable} with the specified color.
+     * @param color The color to make the {@link Drawable}.
+     */
+    public IconHighlightDrawable(@ColorRes int color) {
+        setShape(new OvalShape());
+        setAlpha(75);
+        getPaint().setColor(color);
+        startAnimation();
+    }
+
+    @Override
+    public void draw(Canvas canvas) {
+        canvas.save();
+        canvas.scale(mScale, mScale, getBounds().exactCenterX(), getBounds().exactCenterY());
+        super.draw(canvas);
+        canvas.restore();
+    }
+
+    @Override
+    public void setBounds(Rect bounds) {
+        mCacheRect.set(bounds.left + mMargin.left, bounds.top + mMargin.top,
+                bounds.right - mMargin.right, bounds.bottom - mMargin.bottom);
+        makeSquare(mCacheRect);
+        super.setBounds(mCacheRect);
+    }
+
+    @Override
+    public void setBounds(int left, int top, int right, int bottom) {
+        mCacheRect.set(left + mMargin.left, top + mMargin.top, right - mMargin.right,
+                bottom - mMargin.bottom);
+        makeSquare(mCacheRect);
+        super.setBounds(mCacheRect.left, mCacheRect.top, mCacheRect.right, mCacheRect.bottom);
+    }
+
+    /** How much to inset the {@link Drawable} bounds by. */
+    public void setMargin(int left, int top, int right, int bottom) {
+        mMargin.set(left, top, right, bottom);
+        setBounds(getBounds());
+    }
+
+    /**
+     * Sets the scale of the circle this {@link Drawable} draws.
+     * @param scale The scale (from 0.f to 1.f).
+     */
+    public void setScale(float scale) {
+        mScale = scale;
+        invalidateSelf();
+    }
+
+    private void startAnimation() {
+        final float minScale = 0.8f;
+        final float maxScale = 1.f;
+        setScale(minScale);
+        ObjectAnimator scaleUpAnim = ObjectAnimator.ofFloat(this, "scale", minScale, maxScale);
+        scaleUpAnim.setStartDelay(500);
+        scaleUpAnim.setDuration(500);
+        scaleUpAnim.setInterpolator(PathInterpolatorCompat.create(.8f, 0.f, .6f, 1.f));
+
+        ObjectAnimator scaleDownAnim = ObjectAnimator.ofFloat(this, "scale", maxScale, minScale);
+        scaleDownAnim.setDuration(250);
+        scaleDownAnim.setInterpolator(PathInterpolatorCompat.create(.8f, 0.f, .6f, 1.f));
+
+        AnimatorSet set = new AnimatorSet();
+        set.playSequentially(scaleUpAnim, scaleDownAnim);
+        set.addListener(new AnimatorListenerAdapter() {
+            private boolean mCanceled;
+
+            @Override
+            public void onAnimationStart(Animator animation) {
+                mCanceled = false;
+            }
+
+            @Override
+            public void onAnimationCancel(Animator animation) {
+                mCanceled = true;
+            }
+
+            @Override
+            public void onAnimationEnd(Animator animation) {
+                if (!mCanceled) animation.start();
+            }
+        });
+        set.start();
+    }
+
+    private void makeSquare(Rect rect) {
+        int minDimension = Math.min(rect.width(), rect.height());
+        rect.inset((rect.width() - minDimension) / 2, (rect.height() - minDimension) / 2);
+    }
+}