Upstream oodles of Chrome for Android code into Chromium.

chrome/android/java_staging/src/org/chromium/chrome/browser/enhancedbookmarks/EnhancedBookmarkDetailScrollView.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.enhancedbookmarks;
+
+import android.content.Context;
+import android.util.AttributeSet;
+import android.widget.ScrollView;
+
+import com.google.android.apps.chrome.R;
+
+/**
+ * Customized ScrollView used in EnhancedBookmarkDetailDialog. This ScrollView broadcasts scroll
+ * change events and computes height compensation value used in detail dialog.
+ */
+public class EnhancedBookmarkDetailScrollView extends ScrollView {
+
+    /**
+     * Listener for scroll change event of the scrollView.
+     */
+    public interface OnScrollListener {
+        void onScrollChanged(int y, int oldY);
+    }
+
+    private int mHeightCompensation;
+    // Maximum scroll amount by pixels in Y direction (height).
+    private int mMaximumScrollY;
+    private OnScrollListener mScrollListener;
+
+    public EnhancedBookmarkDetailScrollView(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        mHeightCompensation =
+                getResources().getDimensionPixelSize(R.dimen.enhanced_bookmark_detail_image_height)
+                - getResources().getDimensionPixelSize(R.dimen.toolbar_height_no_shadow);
+    }
+
+    /**
+     * Sets scroll listener that is called whenever scrollY changes.
+     */
+    public void setOnScrollListener(OnScrollListener listener) {
+        mScrollListener = listener;
+    }
+
+    /**
+     * Gets height compensation, a fixed length that scroll view uses to extend its length if
+     * content is not long enough.
+     */
+    public int getHeightCompensation() {
+        return mHeightCompensation;
+    }
+
+    /**
+     * Gets the maximum value scrollY can be. MaximumScrollY should never be less than
+     * HeightCompensation.
+     */
+    public int getMaximumScrollY() {
+        return mMaximumScrollY;
+    }
+
+    @Override
+    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
+        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
+        int childHeight = getChildAt(0).getMeasuredHeight();
+        mMaximumScrollY = childHeight > getMeasuredHeight() ? childHeight - getMeasuredHeight() : 0;
+    }
+
+    @Override
+    protected void onScrollChanged(int x, int y, int oldx, int oldy) {
+        if (mScrollListener == null) return;
+        mScrollListener.onScrollChanged(y, oldy);
+    }
+}