Repeat thead and tfoot when table contains page breaks

This has been done a few times before[0][1], but seems to be broken
again as reported in [2].

This commit is only reinstating what's missing from [1]. This was done
by running:

    git log -p -1 2d778f6 | git apply -3 -p6 --directory=src/qt/qtwebkit

And resolving the conflicts. There are still some compile errors. These
will be fixed in the upcoming commits instead of in this one to clarify
the changes.

This change doesn't completely fix the issue. The thead/tfoot block is
drawn again on the next page, however the other content is not shifted
down accordingly. This means that the thead/tfoot block on the next page
will be placed on top of the continued table instead of above it.

[0]: ariya#211
[1]: ariya#344
[2]: ariya#13324

src/qt/qtwebkit/Source/WebCore/rendering/RenderTable.cpp

@@ -670,7 +670,59 @@ void RenderTable::paintObject(PaintInfo& paintInfo, const LayoutPoint& paintOffs
             child->paint(info, childPoint);
         }
     }
-
+
+    bool repaintedHead = false;
+    IntPoint repaintedHeadPoint;
+    bool repaintedFoot = false;
+    IntPoint repaintedFootPoint;
+    if (view()->pageLogicalHeight()) {
+        // re-paint header/footer if table is split over multiple pages
+        if (m_head) {
+            IntPoint childPoint = flipForWritingMode(m_head, IntPoint(tx, ty), ParentToChildFlippingAdjustment);
+            if (!info.rect.contains(childPoint.x() + m_head->x(), childPoint.y() + m_head->y())) {
+                repaintedHeadPoint = IntPoint(childPoint.x(), info.rect.y() - m_head->y());
+                repaintedHead = true;
+                dynamic_cast<RenderObject*>(m_head)->paint(info, repaintedHeadPoint.x(), repaintedHeadPoint.y());
+            }
+        }
+        if (m_foot) {
+            IntPoint childPoint = flipForWritingMode(m_foot, IntPoint(tx, ty), ParentToChildFlippingAdjustment);
+            if (!info.rect.contains(childPoint.x() + m_foot->x(), childPoint.y() + m_foot->y())) {
+                // find actual end of table on current page
+                int dy = 0;
+                const int max_dy = info.rect.y() + info.rect.height();
+                const int vspace = vBorderSpacing();
+                for (RenderObject* section = firstChild(); section; section = section->nextSibling()) {
+                    if (section->isTableSection()) {
+                        if (toRenderBox(section)->y() > max_dy) {
+                            continue;
+                        }
+                        int i = 0;
+                        for(RenderObject* row = section->firstChild(); row; row = row->nextSibling()) {
+                            if (!row->isTableRow()) {
+                                continue;
+                            }
+                            // get actual bottom-y position of this row - pretty complicated, how could this be simplified?
+                            // note how we have to take the rowPoint and section's y-offset into account, see e.g.
+                            // RenderTableSection::paint where this is also done...
+                            IntPoint rowPoint = flipForWritingMode(toRenderBox(row), IntPoint(tx, ty), ParentToChildFlippingAdjustment);
+                            int row_dy = rowPoint.y() + toRenderBox(row)->y() + toRenderBox(row)->logicalHeight() + toRenderBox(section)->y();
+                            if (row_dy < max_dy && row_dy > dy) {
+                                dy = row_dy;
+                            } else if (row_dy > max_dy) {
+                                break;
+                            }
+                            i++;
+                        }
+                    }
+                }
+                repaintedFoot = true;
+                repaintedFootPoint = IntPoint(childPoint.x(), dy - m_foot->y());
+                dynamic_cast<RenderObject*>(m_foot)->paint(info, repaintedFootPoint.x(), repaintedFootPoint.y());
+            }
+        }
+    }
+
     if (collapseBorders() && paintPhase == PaintPhaseChildBlockBackground && style()->visibility() == VISIBLE) {
         recalcCollapsedBorders();
         // Using our cached sorted styles, we then do individual passes,
@@ -681,6 +733,12 @@ void RenderTable::paintObject(PaintInfo& paintInfo, const LayoutPoint& paintOffs
             m_currentBorder = &m_collapsedBorders[i];
             for (RenderTableSection* section = bottomSection(); section; section = sectionAbove(section)) {
                 LayoutPoint childPoint = flipForWritingModeForChild(section, paintOffset);
+                // also repaint borders of header/footer if required
+                if (section == m_head && repaintedHead) {
+                    childPoint = repaintedHeadPoint;
+                } else if (section == m_foot && repaintedFoot) {
+                    childPoint = repaintedFootPoint;
+                }
                 section->paint(info, childPoint);
             }
         }