toDataURL can return an empty image in some cases

[Dean Jackson]

In some accelerated rendering cases, toDataURL can produce an empty image on canvas elements, especially if that canvas element is not on-screen.

<rdar://problem/13760256>

[Dean Jackson]

Created attachment 201482 [details]
Patch

[Darin Adler]

Comment on attachment 201482 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=201482&action=review

> Source/WebCore/platform/graphics/cg/ImageBufferCG.cpp:453
> +        CGContextFlush(context()->platformContext());
> +#if !PLATFORM(IOS) && __MAC_OS_X_VERSION_MIN_REQUIRED == 1070
> +        m_data.m_lastFlushTime = currentTimeMS();
> +#endif

Could we make this share code with the ImageBuffer::context flush? Or is that not worth it?

[Dean Jackson]

Comment on attachment 201482 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=201482&action=review

>> Source/WebCore/platform/graphics/cg/ImageBufferCG.cpp:453
>> +#endif
> 
> Could we make this share code with the ImageBuffer::context flush? Or is that not worth it?

There were a bunch of places which called flush in this manner. I did consider gathering them all so that we didn't have the ugly #if spewing across the whole file. I'll take another look before committing.

[Dean Jackson]

Created attachment 201632 [details]
Patch for landing

[Dean Jackson]

Committed r150040: <http://trac.webkit.org/changeset/150040>