Add support for highlighting menu items

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

Index: chrome/android/java/src/org/chromium/chrome/browser/appmenu/PulseDrawableFactory.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/appmenu/PulseDrawableFactory.java b/chrome/android/java/src/org/chromium/chrome/browser/appmenu/PulseDrawableFactory.java
new file mode 100644
index 0000000000000000000000000000000000000000..122e3a9aea03038373ca3b85279603d869bedf2c
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/appmenu/PulseDrawableFactory.java
@@ -0,0 +1,68 @@
+// 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.graphics.Canvas;
+import android.graphics.Paint;
+import android.graphics.Rect;
+import android.support.v4.view.animation.FastOutSlowInInterpolator;
+import android.support.v4.view.animation.PathInterpolatorCompat;
+
+import org.chromium.base.ContextUtils;
+import org.chromium.chrome.R;
+import org.chromium.chrome.browser.util.MathUtils;
+
+/**
+ * A helper factory to create {@link PulseDrawable}s.
+ */
+public class PulseDrawableFactory {
+    /**
+     * Creates a {@link PulseDrawable} that will fill the bounds with a pulsing color.
+     * @return A new {@link PulseDrawable} instance.
+     */
+    public static PulseDrawable createHighlight() {
+        PulseDrawable.Painter painter = new PulseDrawable.Painter() {
+            @Override
+            public void modifyDrawable(PulseDrawable drawable, float interpolation) {
+                drawable.setAlpha((int) MathUtils.interpolate(12, 75, interpolation));
+            }
+
+            @Override
+            public void draw(
+                    PulseDrawable drawable, Paint paint, Canvas canvas, float interpolation) {
+                canvas.drawRect(drawable.getBounds(), paint);
+            }
+        };
+
+        return new PulseDrawable(ContextUtils.getApplicationContext().getResources(),
+                R.color.google_blue_500, new FastOutSlowInInterpolator(), painter);
+    }
+
+    /**
+     * Creates a {@link PulseDrawable} that will draw a pulsing circle inside the bounds.
+     * @return A new {@link PulseDrawable} instance.
+     */
+    public static PulseDrawable createCircle() {
+        PulseDrawable.Painter painter = new PulseDrawable.Painter() {
+            @Override
+            public void modifyDrawable(PulseDrawable drawable, float interpolation) {
+                drawable.invalidateSelf();
+            }
+
+            @Override
+            public void draw(
+                    PulseDrawable drawable, Paint paint, Canvas canvas, float interpolation) {
+                Rect bounds = drawable.getBounds();
+                float scale = MathUtils.interpolate(0.8f, 1.f, interpolation);
+                float radius = Math.min(bounds.width(), bounds.height()) * scale;
+                canvas.drawCircle(bounds.exactCenterX(), bounds.exactCenterY(), radius, paint);
+            }
+        };
+
+        return new PulseDrawable(ContextUtils.getApplicationContext().getResources(),
+                R.color.google_blue_500, PathInterpolatorCompat.create(.8f, 0.f, .6f, 1.f),
+                painter);
+    }
+}