Bug 1030993 - Basic reflow implementation for ruby frame classes. r=dbaron

To account for spacing between bases or text boxes during reflow, the line
layout which manages the bases updates its inline direction coordinate based on
the preferred inline size for the corresponding text boxes. Next, the base is
reflowed at the correct inline coordinate. Each paired text box is then also
reflowed at the proper inline position determined by (1) the current position of
its corresponding base and (2) its own preferred width.

In computing intrinsic widths, accounting for spacing is less complicated. The
minimum intrinsic width is the width of the widest ruby column, and the
preferred intrinsic width is the sum of all the ruby column widths. Each ruby
column width is the maximum width of its base box and text boxes. These
individual widths are determined using GetPrefISize on the base and text boxes.

Ruby base container frames store a list of pointers to the ruby text container
frames in the segment they denote. This list of pointers is created in the ruby
frame reflow method before calling the reflow method for the ruby base
container. The list exists and is used only during reflow of the main ruby frame
and is cleared before returning from reflow.
Bug 1039017 - Reftests for ruby whitespace handling. r=dholbert
Bug 1030993 - Fix assertion failure in reftest css-ruby/ruby-whitespace-1.html. r=dbaron

Fixes the assertion failure with text:
"###!!! ASSERTION: Wrong line container
hint: '!aForFrame || (aLineContainer == FindLineContainer(aForFrame) ||
aLineContainer->GetType() == nsGkAtoms::rubyTextContainerFrame ||
(aLineContainer->GetType() == nsGkAtoms::letterFrame &&
aLineContainer->IsFloating()))', file
/home/sgbowen/builds/mozilla-central/layout/generic/nsTextFrame.cpp, line 1259"
which occasionally appears when opening pages with ruby or when running ruby
reftests.

Updates the manifest for ruby reftests to the current expectations (adjust
assertion counts, etc.)
Bug 1030993 - Reftests for Ruby reflow implementation.r=dbaron
Bug 1030993 followup - Annotate ruby reftests directory as skip-if(B2G), pending investigation on followup bug.