Generate toCSSFooValue for CSS*GradientValues

Generate toCSSFooValue for CSS*GradientValues

As a step to use toCSSFooValue(), this cl generates toCSSGradientValue,
toCSSLinearGradientValue and toCSSRadialGradientValue. To generate them,
isLinearGradient(), isRadialGradient() need to have *Value* as a postfix.

To be consistent with other isFooValue(), they're moved from CSSGradientValue
to CSSValue.

Generate toCSSFooValue() for CSSGradiendValue, CSSLinearGradientValue and CSSRadialGradientValue

BUG=N/A

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=158596

[gyuyoung-inactive, 2013-09-30 11:00:54]

Add tkent.

[tkent, 2013-09-30 23:54:37]

https://chromiumcodereview.appspot.com/25044003/diff/1/Source/core/css/CSSGra...
File Source/core/css/CSSGradientValue.cpp (right):

https://chromiumcodereview.appspot.com/25044003/diff/1/Source/core/css/CSSGra...
Source/core/css/CSSGradientValue.cpp:67: ASSERT(isRadialGradientValue());
This assertion is redundant.

[gyuyoung-inactive, 2013-10-01 02:27:42]

https://chromiumcodereview.appspot.com/25044003/diff/1/Source/core/css/CSSGra...
File Source/core/css/CSSGradientValue.cpp (right):

https://chromiumcodereview.appspot.com/25044003/diff/1/Source/core/css/CSSGra...
Source/core/css/CSSGradientValue.cpp:67: ASSERT(isRadialGradientValue());
On 2013/09/30 23:54:37, tkent wrote:
> This assertion is redundant.

Exactly right. I missed to remove it. Thx !

[tkent, 2013-10-01 02:35:01]

lgtm

[commit-bot: I haz the power, 2013-10-01 02:35:08]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/gyuyoung.kim@samsung.com/25044003/6001

[commit-bot: I haz the power, 2013-10-01 05:45:20]

Change committed as 158596