Upstream SmoothProgressBar and ToolbarProgressBar

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

Index: chrome/android/java/src/org/chromium/chrome/browser/widget/SmoothProgressBar.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/widget/SmoothProgressBar.java b/chrome/android/java/src/org/chromium/chrome/browser/widget/SmoothProgressBar.java
new file mode 100644
index 0000000000000000000000000000000000000000..1e7542724d2ed29accab5b5116be88da52908547
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/widget/SmoothProgressBar.java
@@ -0,0 +1,96 @@
+// 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.util.AttributeSet;
+import android.widget.ProgressBar;
+
+import org.chromium.base.ApiCompatibilityUtils;
+
+/**
+ * A progress bar that smoothly animates incremental updates.
+ * <p>
+ * Consumers of this class need to be aware that calls to {@link #getProgress()} will return
+ * the currently visible progress value and not the one set in the last call to
+ * {@link #setProgress(int)}.
+ */
+public class SmoothProgressBar extends ProgressBar {
+    private static final int MAX = 100;
+
+    // The amount of time between subsequent progress updates. 16ms is chosen to make 60fps.
+    private static final long PROGRESS_UPDATE_DELAY_MS = 16;
+
+    private boolean mIsAnimated = false;
+    private int mTargetProgress;
+
+    // Since the progress bar is being animated, the internal progress bar resolution should be
+    // at least fine as the width, not MAX. This multiplier will be applied to input progress
+    // to convert to a finer scale.
+    private int mResolutionMutiplier = 1;
+
+    private Runnable mUpdateProgressRunnable = new Runnable() {
+        @Override
+        public void run() {
+            if (getProgress() == mTargetProgress) return;
+            if (!mIsAnimated) {
+                setProgressInternal(mTargetProgress);
+                return;
+            }
+            // Every time, the progress bar get's at least 20% closer to mTargetProcess.
+            // Add 3 to guarantee progressing even if they only differ by 1.
+            setProgressInternal(getProgress() + (mTargetProgress - getProgress() + 3) / 4);
+            ApiCompatibilityUtils.postOnAnimationDelayed(
+                    SmoothProgressBar.this, this, PROGRESS_UPDATE_DELAY_MS);
+        }
+    };
+
+    /**
+     * Create a new progress bar with range 0...100 and initial progress of 0.
+     * @param context the application environment.
+     * @param attrs the xml attributes that should be used to initialize this view.
+     */
+    public SmoothProgressBar(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        setMax(MAX * mResolutionMutiplier);
+    }
+
+    @Override
+    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
+        super.onSizeChanged(w, h, oldw, oldh);
+
+        int normalizedProgress = getProgress() / mResolutionMutiplier;
+
+        // Choose an integer resolution multiplier that makes the scale at least fine as the width.
+        mResolutionMutiplier = Math.max(1, (w + MAX - 1) / MAX);
+        setMax(mResolutionMutiplier * MAX);
+        setProgressInternal(normalizedProgress * mResolutionMutiplier);
+    }
+
+    @Override
+    public void setProgress(int progress) {
+        final int targetProgress = progress * mResolutionMutiplier;
+        if (mTargetProgress == targetProgress) return;
+        mTargetProgress = targetProgress;
+        removeCallbacks(mUpdateProgressRunnable);
+        ApiCompatibilityUtils.postOnAnimation(this, mUpdateProgressRunnable);
+    }
+
+    /**
+     * Sets whether to animate incremental updates or not.
+     * @param isAnimated True if it is needed to animate incremental updates.
+     */
+    public void setAnimated(boolean isAnimated) {
+        mIsAnimated = isAnimated;
+    }
+
+    /**
+     * Called to update the progress visuals.
+     * @param progress The progress value to set the visuals to.
+     */
+    protected void setProgressInternal(int progress) {
+        super.setProgress(progress);
+    }
+}