Show Ash like <select> popup on Android tablets

ui/android/java/src/org/chromium/ui/DropdownPopupWindow.java

Index: ui/android/java/src/org/chromium/ui/DropdownPopupWindow.java
diff --git a/ui/android/java/src/org/chromium/ui/DropdownPopupWindow.java b/ui/android/java/src/org/chromium/ui/DropdownPopupWindow.java
new file mode 100644
index 0000000000000000000000000000000000000000..f4f54affe31d964a329cfd6fb14d440529d692a0
--- /dev/null
+++ b/ui/android/java/src/org/chromium/ui/DropdownPopupWindow.java
@@ -0,0 +1,126 @@
+// Copyright 2014 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.ui;
+
+import android.content.Context;
+import android.view.View;
+import android.view.View.MeasureSpec;
+import android.view.View.OnLayoutChangeListener;
+import android.view.ViewGroup;
+import android.widget.LinearLayout;
+import android.widget.ListAdapter;
+import android.widget.ListPopupWindow;
+
+import org.chromium.ui.base.ViewAndroidDelegate;
+
+/**
+ * The dropdown list popup window.
+ */
+public class DropdownPopupWindow extends ListPopupWindow {
+
+    private final Context mContext;
+    private final ViewAndroidDelegate mViewAndroidDelegate;
+    private final View mAnchorView;
+    private float mAnchorWidth;
+    private float mAnchorHeight;
+    private float mAnchorX;
+    private float mAnchorY;
+    private OnLayoutChangeListener mLayoutChangeListener;
+
+    /**
+     * Creates an DropdownPopupWindow with specified parameters.
+     * @param context Application context.
+     * @param viewAndroidDelegate View delegate used to add and remove views.
+     */
+    public DropdownPopupWindow(Context context, ViewAndroidDelegate viewAndroidDelegate) {
+        super(context, null, 0, R.style.DropdownPopupWindow);
+        mContext = context;
+        mViewAndroidDelegate = viewAndroidDelegate;
+
+        mAnchorView = mViewAndroidDelegate.acquireAnchorView();
+        mAnchorView.setId(R.id.dropdown_popup_window);
+        mAnchorView.setTag(this);
+
+        mLayoutChangeListener = new OnLayoutChangeListener() {
+            @Override
+            public void onLayoutChange(View v, int left, int top, int right, int bottom,
+                    int oldLeft, int oldTop, int oldRight, int oldBottom) {
+                if (v == mAnchorView) DropdownPopupWindow.this.show();
+            }
+        };
+
+        mAnchorView.addOnLayoutChangeListener(mLayoutChangeListener);
+        setAnchorView(mAnchorView);
+    }
+
+    /**
+     * Sets the location and the size of the anchor view that the DropdownPopupWindow will use to
+     * attach itself.
+     * @param x X coordinate of the top left corner of the anchor view.
+     * @param y Y coordinate of the top left corner of the anchor view.
+     * @param width The width of the anchor view.
+     * @param height The height of the anchor view.
+     */
+    public void setAnchorRect(float x, float y, float width, float height) {
+        mAnchorWidth = width;
+        mAnchorHeight = height;
+        mAnchorX = x;
+        mAnchorY = y;
+        if (mAnchorView != null) {
+            mViewAndroidDelegate.setAnchorViewPosition(mAnchorView, mAnchorX, mAnchorY,
+                    mAnchorWidth, mAnchorHeight);
+        }
+    }
+
+    @Override
+    public void show() {
+        // An ugly hack to keep the popup from expanding on top of the keyboard.
+        setInputMethodMode(INPUT_METHOD_NEEDED);
+        super.show();
+        getListView().setDividerHeight(0);
+        int contentWidth = measureContentWidth();
+        float contentWidthInDip = contentWidth /
+                mContext.getResources().getDisplayMetrics().density;
+        if (contentWidthInDip > mAnchorWidth) {
+            setContentWidth(contentWidth);
+        } else {
+            setWidth(ViewGroup.LayoutParams.WRAP_CONTENT);
+        }
+        mViewAndroidDelegate.setAnchorViewPosition(mAnchorView, mAnchorX, mAnchorY, mAnchorWidth,
+                mAnchorHeight);
+    }
+
+    @Override
+    public void dismiss() {
+        super.dismiss();
+        mAnchorView.removeOnLayoutChangeListener(mLayoutChangeListener);
+        mAnchorView.setTag(null);
+        mViewAndroidDelegate.releaseAnchorView(mAnchorView);
+    }
+
+    /**
+     * Measures the width of the list content.
+     * @return The popup window width in pixels.
+     */
+    private int measureContentWidth() {
+        int maxWidth = 0;
+        View itemView = null;
+        final ListAdapter adapter = getListView().getAdapter();
+        if (adapter == null)
+          return 0;
+        final int widthMeasureSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
+        final int heightMeasureSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
+        for (int i = 0; i < adapter.getCount(); i++) {
+            itemView = adapter.getView(i, itemView, null);
+            LinearLayout.LayoutParams params =
+                    new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,
+                            LinearLayout.LayoutParams.WRAP_CONTENT);
+            itemView.setLayoutParams(params);
+            itemView.measure(widthMeasureSpec, heightMeasureSpec);
+            maxWidth = Math.max(maxWidth, itemView.getMeasuredWidth());
+        }
+        return maxWidth;
+    }
+}