WebUsb Android chooser UI

ui/android/java/src/org/chromium/ui/text/NoUnderlineClickableSpan.java

+// Copyright 2016 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.text;
+
+import android.graphics.Color;
+import android.text.TextPaint;
+import android.text.style.ClickableSpan;
+import android.view.View;
+
+/**
+* Show a clickable link with underlines turned off.
+*/
+public class NoUnderlineClickableSpan extends ClickableSpan {
+    @Override
+    public void onClick(View view) {
+        // Get rid of the highlight background on selection.
+        view.invalidate();

[newt (away), 2016/03/15 19:03:54]

Why is this needed? Are you copying this from somewhere?

Ah, looks like this came from BluetoothChooserDialog.NoUnderlineClickableSpan.
But it's not used in any of the other ClickableSpan subclasses in Chrome. Do we
really it? Maybe ask Finnur, who added it.

[Finnur, 2016/03/15 21:11:26]

My ears are burning... ;)

It was definitely useful when I wrote it, because, as I recall, at that time
when a link was clicked in a dialog -- a link that *didn't* result in the dialog
closing -- you'd get this background highlight that would just stick. As if the
intent was to select the URL. Invalidating the view would cause it to redraw and
go away. 

If this no longer happens, then perhaps this class isn't needed, I guess. But it
should be easy to test, though, just use a regular span and click a Refresh link
and see if it grows a background.

[newt (away), 2016/03/15 21:24:45]

Ahhhh, thanks for explaining. So this *might* be needed in the item chooser
dialogs, but definitely isn't needed in other uses of NoUnderlineClickableSpan.

In that case, Jun, could you check whether this is still needed in the item
chooser dialog case, and if so, move the code into the choose dialog(s).
Otherwise, delete this altogether. Thanks!

(Likewise for bgColor = TRANSPARENT below)

[juncai, 2016/03/16 00:40:36]

I did some test and it seems that this is needed for the chooser dialog case.
Otherwise, like Finnur pointed out, if a link click doesn't result in the dialog
closing, the link click would cause the background highlight to stick as if the
link text was selected.

So I removed this function here and moved it to chooser dialog.

Done.

+    }
+
+    // Disable underline on the link text.
+    @Override
+    public void updateDrawState(TextPaint textPaint) {
+        super.updateDrawState(textPaint);
+        textPaint.bgColor = Color.TRANSPARENT;

[newt (away), 2016/03/15 19:03:54]

Also, why set the background color to transparent?

[Finnur, 2016/03/15 21:11:26]

Might be related to the above, not sure. Don't remember. :)

Maybe a background color needed to be set for the whole thing to work. Or maybe
I'm just that much of a rebel to set a transparent background needlessly. I can
be crazy like that.

[juncai, 2016/03/16 00:40:36]

I did some test and it seems that with or without this line, view.invalidate();
works correctly and removes the link click background highlight. So I just
removed this line here.

Done.

[Finnur, 2016/03/16 13:35:14]

Like I said. Coo coo crazy. ;)

[newt (away), 2016/03/16 17:17:16]

I'm sure there was a reason at the time :)

+        textPaint.setUnderlineText(false);
+    }
+}