[css2] Tighten the definition of the content area height for inlines

The previous prose allowed for variations not used in actual
implementations. Since there is interoperability, the spec should align.

Closes w3c#1804

Author: frivoal

css2/visudet.html

@@ -971,12 +971,10 @@ <h3>10.6.1 <a name="inline-non-replaced">Inline, non-replaced elements</a></h3>
 <p>The <a href="visudet.html#propdef-height" class="noxref"><span class="propinst-height">'height'</span></a> property does not
 apply. The height of the content area should be based on the font, but
 this specification does not specify how. A UA may, e.g., use the
-em-box or the maximum ascender and descender of the font. (The latter
+the maximum ascender and descender of the font. (This
 would ensure that glyphs with parts above or below the em-box still
 fall within the content area, but leads to differently sized boxes for
-different fonts; the former would ensure authors can control
-background styling relative to the 'line-height', but leads to glyphs
-painting outside their content area.)
+different fonts.)
 </p>
 <p class=note>Note: level 3 of CSS will probably include a property to
 select which measure of the font is used for the content height.
@@ -989,14 +987,10 @@ <h3>10.6.1 <a name="inline-non-replaced">Inline, non-replaced elements</a></h3>
 the height of the line box.
 </p>
 <p><a name="multi-font-inline-height"></a> If more than one font is
-used (this could happen when glyphs are found in different fonts), the
-height of the content area is not defined by this specification.
-However, we suggest that the height is chosen such that the content
-area is just high enough for either (1) the em-boxes, or (2) the
-maximum ascenders and descenders, of <em>all</em> the fonts in the
-element. Note that this may be larger than any of the font sizes
-involved, depending on the baseline alignment of the fonts.
-</p>
+used (this could happen when glyphs are found in different fonts),
+the height of the content area is not affected
+by the glyphs from the fallback fonts,
+and only depends on the first available font.</p>
 
 <h3>10.6.2 <a name="inline-replaced-height">Inline replaced elements</a>,
 block-level replaced elements in normal flow, 'inline-block' replaced

css2/visudet.src

@@ -896,12 +896,10 @@ href="#min-max-heights">Minimum and maximum heights</a> below.</em>
 <p>The <span class="propinst-height">'height'</span> property does not
 apply. The height of the content area should be based on the font, but
 this specification does not specify how. A UA may, e.g., use the
-em-box or the maximum ascender and descender of the font. (The latter
+the maximum ascender and descender of the font. (This
 would ensure that glyphs with parts above or below the em-box still
 fall within the content area, but leads to differently sized boxes for
-different fonts; the former would ensure authors can control
-background styling relative to the 'line-height', but leads to glyphs
-painting outside their content area.)
+different fonts.)
 </p>
 <p class=note>Note: level 3 of CSS will probably include a property to
 select which measure of the font is used for the content height.
@@ -914,14 +912,10 @@ class="propinst-line-height">'line-height'</span> is used when calculating
 the height of the line box.
 </p>
 <p><a name="multi-font-inline-height"></a> If more than one font is
-used (this could happen when glyphs are found in different fonts), the
-height of the content area is not defined by this specification.
-However, we suggest that the height is chosen such that the content
-area is just high enough for either (1) the em-boxes, or (2) the
-maximum ascenders and descenders, of <em>all</em> the fonts in the
-element. Note that this may be larger than any of the font sizes
-involved, depending on the baseline alignment of the fonts.
-</p>
+used (this could happen when glyphs are found in different fonts),
+the height of the content area is not affected
+by the glyphs from the fallback fonts,
+and only depends on the first available font.</p>
 
 <h3><a name="inline-replaced-height">Inline replaced elements</a>,
 block-level replaced elements in normal flow, 'inline-block' replaced