Add support using EXPECT_EQ with NullableString16 objects.

Add support using EXPECT_EQ with NullableString16 objects.

Change the default constructor to set is_null_ to true.  This makes NullableString16 act more like a WebKit::WebString, which is really the reason NullableString16 exists at all.

R=brettw@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=206805

[darin (slow to review), 2013-06-17 18:44:34]

I'm just carving part of https://codereview.chromium.org/16335022/ out into a
separate CL.  It was really handy to be able to use EXPECT_EQ with
NullableString16 objects.

[brettw, 2013-06-17 20:30:38]

lgtm

[commit-bot: I haz the power, 2013-06-17 20:49:56]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/darin@chromium.org/17289005/1

[darin (slow to review), 2013-06-17 21:37:54]

Committed patchset #1 manually as r206805 (presubmit successful).

[Avi (use Gerrit), 2013-06-18 21:02:42]

https://codereview.chromium.org/17289005/diff/1/base/strings/nullable_string1...
File base/strings/nullable_string16.cc (right):

https://codereview.chromium.org/17289005/diff/1/base/strings/nullable_string1...
base/strings/nullable_string16.cc:5: #include "base/nullable_string16.h"
I'll eventually fix this up, but this should be base/strings/nullable_string16.h
:)

[darin (slow to review), 2013-06-18 21:35:19]

On 2013/06/18 21:02:42, Avi wrote:
>
https://codereview.chromium.org/17289005/diff/1/base/strings/nullable_string1...
> File base/strings/nullable_string16.cc (right):
> 
>
https://codereview.chromium.org/17289005/diff/1/base/strings/nullable_string1...
> base/strings/nullable_string16.cc:5: #include "base/nullable_string16.h"
> I'll eventually fix this up, but this should be
base/strings/nullable_string16.h
> :)

Oops, I had originally developed the CL before you moved nullable_string16.h
into base/strings/