Merge 108111 - REGRESSION: empty span creates renders with non-zero height

Merge 108111 - REGRESSION: empty span creates renders with non-zero height
https://bugs.webkit.org/show_bug.cgi?id=76465

Reviewed by David Hyatt.

Source/WebCore:

Tests: fast/css/empty-span.html
       fast/css/non-empty-span.html

Empty inlines with line-height, vertical-alignment or font metrics should only get a linebox if there is some
other content in the line. So only create line boxes for such elements on lines that are not empty.

This patch fixes a regression where an empty inline with line-height was propagating its height to an empty line.
It also fixes cases where lines with content that had a leading empty inline element weren't respecting the
vertical alignment or font-height of the empty inline.

* rendering/RenderBlockLineLayout.cpp:
(WebCore::RenderBlock::constructLine): only create line boxes for lines that are not empty.
(WebCore::requiresLineBoxForContent): an inline flow with line-height, vertical-alignment, or font-size
 will need a linebox if the rest of the line is not empty.
(WebCore):
(WebCore::alwaysRequiresLineBox): rename from inlineFlowRequiresLineBox.
(WebCore::requiresLineBox):
(WebCore::RenderBlock::LineBreaker::nextLineBreak): if the inline flow definitely requires a line, mark
 the line non-empty - otherwise hold off.

LayoutTests:

* fast/css/empty-span-expected.html: Added.
* fast/css/empty-span.html: Added.
* fast/css/non-empty-span.html: Added.
* platform/chromium/test_expectations.txt: Suppress result until rebaseline on MAC and WIN.
* platform/chromium-linux-x86/fast/css/non-empty-span-expected.png: Added.
* platform/chromium-linux-x86/fast/css/non-empty-span-expected.txt: Added.

TBR=robert@webkit.org
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=109047