Fixed perf regression by removing tree traversal for text sibling.
Changed contents of HeapHashMap on Document to store a new struct
StyleRecalcData containing both the original ComputedStyle and
the next Text sibling.
Deleted Node::nextTextSibling method that traverses the tree to find
the next text sibling, replaced usage of this method with access to
the Text node from the StyleRecalcData.
Patch yields a 79.21% performance improvement to
blink_perf.dom:select-single-remove benchmark on mac-10-10 bot:
http://storage.googleapis.com/chromium-telemetry/html-results/results-2016-11-06_17-33-01
BUG=659647
Review-Url: https://codereview.chromium.org/2476163002
Cr-Commit-Position: refs/heads/master@{#432324}
9 files changed
