[css-inline-3] Apply css2 patch for 10.8

Based on Pull Request #1993 to solve issue #1796

Author: frivoal

css-inline-3/Overview.bs

@@ -407,24 +407,38 @@ each other by their relevant baselines. Then, for
 each glyph, determine the <var>A</var> and <var>D</var>. Note that
 glyphs in a single element may come from different fonts and thus need
 not all have the same <var>A</var> and <var>D</var>. If the inline box
-contains no glyphs at all, it is considered to contain a <a
+contains no glyphs at all,
+or if it contains only glyphs from fallback fonts,
+it is considered to contain a <a
 href="#strut">strut</a> (an invisible glyph of zero width) with the
 <var>A</var> and <var>D</var> of the element's first available font.
 
-<p>Still for each glyph, determine the leading <var>L</var> to add,
+<p id="inline-box-height">When the value of the <span class="propinst-line-heigh">'line-height'</span> property
+is something other than 'normal',
+determine the leading <var>L</var> to add,
 where <var>L</var> = <span
-class="propinst-line-height">'line-height'</span> - <var>AD</var>. Half
-the leading is added above <var>A</var> and the other half below
-<var>D</var>, giving the glyph and its leading a total height above
+class="propinst-line-height">'line-height'</span> - <var>AD</var> of the first available font.
+Half the leading is added above <var>A</var> of the first available font, and the other half below
+<var>D</var> of the first available font, giving a total height above
 the baseline of <var>A'</var> = <var>A</var> + <var>L</var>/2 and a
 total depth of <var>D'</var> = <var>D</var> + <var>L</var>/2.
+Glyphs from fonts other than the first available font
+do not impact the height or baseline of the inline box
+for <span class="propinst-line-heigh">'line-height'</span> values other than 'normal'.
 
 <p class=note><strong>Note.</strong> <var>L</var> may be negative.
 
-<p id="inline-box-height">The height of the inline box encloses all
-glyphs and their half-leading on each side and is thus exactly
-'line-height'. Boxes of
-child elements do not influence this height.
+<p>Boxes of child elements do not influence this height.
+
+<p>When the value of the <span class="propinst-line-heigh">'line-height'</span> property
+is 'normal',
+the height of the inline box encloses all glyphs, going from the highest <var>A</var> to the deepest <var>D</var>.
+
+<p>User Agents may use different sets of font metrics when determining <var>A</var> and <var>D</var>
+depending on whether the <span class="propinst-line-heigh">'line-height'</span> property
+is 'normal' or some other value,
+for instance taking external leading metrics into account
+only in the 'normal' case.
 
 <p>Although margins, borders, and padding of non-replaced elements do
 not enter into the line box calculation, they are still rendered
@@ -474,13 +488,9 @@ height.
 
 <dl>
 <dt><strong>normal</strong> </dt>
-<dd>Tells user agents to set the used
-value to a "reasonable" value based on the font of the element. The
-value has the same meaning as <span class="index-inst"
-title="&lt;number&gt;"><span
-class="value-inst-number">&lt;number&gt;</span></span>. We recommend a
-used value for 'normal' between 1.0 to 1.2. The <a
-href="cascade.html#computed-value">computed value</a> is 'normal'.
+<dd>Tells user agents to determine the height of the inline box
+automatically based on font metrics.
+See above for details.
 </dd>
 <dt><span class="index-inst" title="&lt;length&gt;"><span
 class="value-inst-length"><strong>&lt;length&gt;</strong></span></span>
@@ -515,11 +525,6 @@ div { line-height: 120%; font-size: 10pt }    /* percentage */
 </pre>
 </div>
 
-<p>When an element contains text that is rendered
-in more than one font, user agents may determine the 'normal' <span
-class="propinst-line-height">'line-height'</span> value according to
-the largest font size.
-</p>
 <p class=note><em><strong>Note.</strong> When there is only one value of <span
 class="propinst-line-height">'line-height'</span> (other than 'normal') for all inline
 boxes in a block container box and they all use the same first available font (and