This was was cloned from bug 15035 as part of operation convergence.
Originally filed: 2011-12-02 00:35:00 +0000

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 #0   contributor@whatwg.org                          2011-12-02 00:35:38 +0000 
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Specification: http://www.whatwg.org/specs/web-apps/current-work/
Multipage: http://www.whatwg.org/C#the-iframe-element
Complete: http://www.whatwg.org/c#the-iframe-element

Comment:
"the height of the bounding box around the content" is not precise enough. 
Does it include floats?  Absolutely positioned elements?  Fixed positioned
elements?  (If so, how.)  Box shadows and other visual effects?

Posted from: 159.63.23.38
User agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0a1) Gecko/20100101 Firefox/11.0a1
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 #1   L. David Baron (Mozilla)                        2011-12-02 00:37:54 +0000 
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And, to be clear, I'm referring to this item within the definition of the seamless attribute on iframe:

 # In visual media, in a CSS-supporting user agent: the user agent should set
 # the intrinsic height of the iframe to the height of the bounding box around
 # the content rendered in the iframe at its current width (as given in the
 # previous bullet point), as it would be if the scrolling position was such
 # that the top of the viewport for the content rendered in the iframe was
 # aligned with the origin of that content's canvas.
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 #2   Ian 'Hixie' Hickson                             2011-12-07 23:24:28 +0000 
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It includes whatever would cause normal overflow for the purpose of rendering scrollbars. Any idea how to phrase that?
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 #3   L. David Baron (Mozilla)                        2011-12-08 00:10:45 +0000 
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Maybe something like:

In visual media, in a CSS-supporting user agent: the user agent should set the intrinsic height of the iframe to the smallest height that would make the content rendered in the iframe at its current width (as given in the previous bullet point) have no scrollable overflow at its bottom edge.  Scrollable overflow is any overflow that would increase the range to which a scrollbar or other scrolling mechanism can scroll.

(Should this text at some point be written so it works for vertical writing?)
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