[CSS Grid Layout] Fix missing layout in flexible and content sized columns

RenderGrid::logicalContentHeightForChild() is called for some items at 
the beginning of RenderGrid::layoutGridItems() from 
RenderGrid::computeUsedBreadthOfGridTracks(). This causes that the
comparison inside the for loop in RenderGrid::layoutGridItems() does not
detect width changes, so elements won't be marked as needsLayout.

So the comparison is done in RenderGrid::logicalContentHeightForChild()
and the element is marked to perform a layout if the width has changed.

The issue can be reproduced easily with a simple grid with one flexible 
or content sized column, all the available width is not used. On top
of that, when you resize the window the flexible or content sized 
columns are not updating their size properly.

Perftest Layout/auto-grid-lots-of-data.html is around 4% worse, which is
expected as we're adding a missing layout.

TEST=fast/css-grid-layout/flex-content-sized-column-use-available-width.html,fast/css-grid-layout/flex-content-sized-columns-resize.html

Review URL: https://codereview.chromium.org/146833018

git-svn-id: svn://svn.chromium.org/blink/trunk@166914 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add myself to modules/OWNERS (for inspector agents that are now under modules).

R=abarth@chromium.org

Review URL: https://codereview.chromium.org/148153021

git-svn-id: svn://svn.chromium.org/blink/trunk@166915 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Start moving StyleSheetContents into the GC managed heap.

BUG=341815

Review URL: https://codereview.chromium.org/148153023

git-svn-id: svn://svn.chromium.org/blink/trunk@166916 bbb929c8-8fbe-4397-9dbb-9b2b20218538