Col width is not honored when dynamically updated and it would not make table narrower

Source/core/rendering/RenderTableCol.cpp

Index: Source/core/rendering/RenderTableCol.cpp
diff --git a/Source/core/rendering/RenderTableCol.cpp b/Source/core/rendering/RenderTableCol.cpp
index ea17126a73baff085f968bc15ccbfa1264e6e43f..d7d6db656f36760b881a87df1b136d81dec29ceb 100644
--- a/Source/core/rendering/RenderTableCol.cpp
+++ b/Source/core/rendering/RenderTableCol.cpp
@@ -57,8 +57,25 @@ void RenderTableCol::styleDidChange(StyleDifference diff, const RenderStyle* old
     // If border was changed, notify table.
     if (parent()) {
         RenderTable* table = this->table();
-        if (table && !table->selfNeedsLayout() && !table->normalChildNeedsLayout() && oldStyle && oldStyle->border() != style()->border())
+        if (table && !table->selfNeedsLayout() && !table->normalChildNeedsLayout() && oldStyle && oldStyle->border() != style()->border()) {
             table->invalidateCollapsedBorders();
+        } else if (oldStyle && oldStyle->logicalWidth() != style()->logicalWidth()) {
+            // FIXME : setPreferredLogicalWidthsDirty is done for all cells as of now.
+            // Need to find a better way so that only the cells which are changed by
+            // the col width should have preferred logical widths recomputed.

[mstensho (USE GERRIT), 2015/01/09 21:21:35]

-"should".

+            table->recalcSectionsIfNeeded();

[mstensho (USE GERRIT), 2015/01/09 21:21:35]

See https://codereview.chromium.org/208263013/#msg11

How about walking the render tree (to find each cell) here, instead of using
things that rely on section ordering and grids being up-to-date? That way you
won't have to call recalcSectionsIfNeeded().

+            unsigned nEffCols = table->numEffCols();
+            for (RenderTableSection* section = table->topSection(); section; section = table->sectionBelow(section)) {
+                for (unsigned j = 0; j < nEffCols; j++) {
+                    for (unsigned i = 0; i < section->numRows(); i++) {
+                        RenderTableCell* cell = section->primaryCellAt(i, j);
+                        if (!cell)
+                            continue;
+                        cell->setPreferredLogicalWidthsDirty();
+                    }
+                }
+            }
+        }
     }
 }