Introduce toHTMLFrameElement

Introduce toHTMLFrameElement

To avoid direct use of static_cast, this patch introduces toHTMLFrameElement for code cleanup.

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=154387

[kangil_, 2013-07-17 07:25:37]

review please? :)

[haraken, 2013-07-17 07:26:42]

LGTM

[commit-bot: I haz the power, 2013-07-17 07:30:59]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/kangil.han@samsung.com/19504005/1

[commit-bot: I haz the power, 2013-07-17 09:21:36]

Change committed as 154387

[Stephen White, 2013-07-17 15:47:55]

On 2013/07/17 09:21:36, I haz the power (commit-bot) wrote:
> Change committed as 154387

This change seems to be causing asserts on many layout tests on Linux Debug,
e.g., accessibility/scroll-to-global-point-iframe-nested.html:

crash log for renderer (pid 17024):
STDOUT: #CRASHED - renderer (pid 17024)
STDERR: ASSERTION FAILED: !node || node->hasTagName(HTMLNames::frameTag)
STDERR: ../../third_party/WebKit/Source/core/html/HTMLFrameElement.h(57) :
WebCore::HTMLFrameElement* WebCore::toHTMLFrameElement(WebCore::Node*)
STDERR: 1   0x7f7dbe2c9ee5
STDERR: 2   0x7f7dbe2f75e9
STDERR: 3   0x7f7dbe2f7a3c
STDERR: 4   0x7f7dbe2f7a3c
STDERR: 5   0x7f7dbe35cd7a

[tkent, 2013-07-17 21:17:44]

https://chromiumcodereview.appspot.com/19504005/diff/1/Source/core/rendering/...
File Source/core/rendering/RenderLayer.cpp (left):

https://chromiumcodereview.appspot.com/19504005/diff/1/Source/core/rendering/...
Source/core/rendering/RenderLayer.cpp:2247: frameElement =
static_cast<HTMLFrameElement*>(ownerElement);
We have a bad cast here though it is harmless.

ownerElement can be an HTML*I*FrameElement, and the code casts it to
HTMLFrameElement.
|frameElement| and the first argument of frameElementAndViewPermitScroll()
should be HTMLFrameElementBase* instead of HTMLFrameElement*.