Add toWebTextAreaElement

Add toWebTextAreaElement

We should check isHTMLTextAreaElement before casting.

BUG=358235

[keishi, 2014-05-19 05:25:19]

Chromium side: https://codereview.chromium.org/295603002/

[tkent, 2014-05-19 05:29:50]

https://codereview.chromium.org/287313003/diff/1/Source/web/WebTextAreaElemen...
File Source/web/WebTextAreaElement.cpp (right):

https://codereview.chromium.org/287313003/diff/1/Source/web/WebTextAreaElemen...
Source/web/WebTextAreaElement.cpp:61: if
(!isHTMLTextAreaElement(*webElement->unwrap<Element>()))
This will crash if webElement is nullptr.  Is it expected?

https://codereview.chromium.org/287313003/diff/1/public/web/WebTextAreaElement.h
File public/web/WebTextAreaElement.h (right):

https://codereview.chromium.org/287313003/diff/1/public/web/WebTextAreaElemen...
public/web/WebTextAreaElement.h:62: BLINK_EXPORT WebTextAreaElement*
toWebTextAreaElement(WebElement*);
Please add a comment for a behavior in case that the specified pointer is
nullptr or a non-TextArea.

[keishi, 2014-05-19 08:24:00]

https://codereview.chromium.org/287313003/diff/1/Source/web/WebTextAreaElemen...
File Source/web/WebTextAreaElement.cpp (right):

https://codereview.chromium.org/287313003/diff/1/Source/web/WebTextAreaElemen...
Source/web/WebTextAreaElement.cpp:61: if
(!isHTMLTextAreaElement(*webElement->unwrap<Element>()))
On 2014/05/19 05:29:51, tkent wrote:
> This will crash if webElement is nullptr.  Is it expected?

toWebInputElement was written like this. We are returning null for non textarea
elements so I have added a null check here.

https://codereview.chromium.org/287313003/diff/1/public/web/WebTextAreaElement.h
File public/web/WebTextAreaElement.h (right):

https://codereview.chromium.org/287313003/diff/1/public/web/WebTextAreaElemen...
public/web/WebTextAreaElement.h:62: BLINK_EXPORT WebTextAreaElement*
toWebTextAreaElement(WebElement*);
On 2014/05/19 05:29:51, tkent wrote:
> Please add a comment for a behavior in case that the specified pointer is
> nullptr or a non-TextArea.

Done.

[tkent, 2014-05-19 08:44:14]

lgtm.

toWebTextAreaElement doesn't follow Blink's common toFoo behavior.  However it's
acceptable because of consistency with toWebInputElement.

[Ilya Sherman, 2014-05-19 08:45:17]

On 2014/05/19 08:44:14, tkent wrote:
> lgtm.
> 
> toWebTextAreaElement doesn't follow Blink's common toFoo behavior.  However
it's
> acceptable because of consistency with toWebInputElement.

What is the common toFoo behavior in Blink?  Perhaps it would make sense to
update toWebInputElement to match?

[tkent, 2014-05-19 08:55:50]

On 2014/05/19 08:45:17, Ilya Sherman wrote:
> > toWebTextAreaElement doesn't follow Blink's common toFoo behavior.  However
> it's
> > acceptable because of consistency with toWebInputElement.
> 
> What is the common toFoo behavior in Blink?  Perhaps it would make sense to
> update toWebInputElement to match?

In Blink, toFoo function should be a wrapper of static_cast<Foo*> with
ASSERT_WITH_SECURITY_IMPLICATION.
The assertion fails if the specified pointer is neither Foo* nor nullptr.
http://src.chromium.org/viewvc/blink/trunk/Source/wtf/Assertions.h#l367

[Ilya Sherman, 2014-05-19 09:15:14]

On 2014/05/19 08:55:50, tkent wrote:
> On 2014/05/19 08:45:17, Ilya Sherman wrote:
> > > toWebTextAreaElement doesn't follow Blink's common toFoo behavior. 
However
> > it's
> > > acceptable because of consistency with toWebInputElement.
> > 
> > What is the common toFoo behavior in Blink?  Perhaps it would make sense to
> > update toWebInputElement to match?
> 
> In Blink, toFoo function should be a wrapper of static_cast<Foo*> with
> ASSERT_WITH_SECURITY_IMPLICATION.
> The assertion fails if the specified pointer is neither Foo* nor nullptr.
> http://src.chromium.org/viewvc/blink/trunk/Source/wtf/Assertions.h#l367

Ah.  I guess that's semantically different from what we're trying to express,
since we don't know whether the field is a textarea or not.  Is there an isFoo
concept in Blink?