Move ExpandToParagraphBoundary to VisibleUnits

third_party/WebKit/Source/core/editing/VisibleUnits.cpp

Index: third_party/WebKit/Source/core/editing/VisibleUnits.cpp
diff --git a/third_party/WebKit/Source/core/editing/VisibleUnits.cpp b/third_party/WebKit/Source/core/editing/VisibleUnits.cpp
index a234656ab5f420fdfc89510245cc750322b15ce5..01bbc7bce3b203a20be0edbfc68ef703c755ce39 100644
--- a/third_party/WebKit/Source/core/editing/VisibleUnits.cpp
+++ b/third_party/WebKit/Source/core/editing/VisibleUnits.cpp
@@ -2143,6 +2143,33 @@ VisiblePosition NextParagraphPosition(const VisiblePosition& p, LayoutUnit x) {
   return pos;
 }
 
+EphemeralRange ExpandToParagraphBoundary(const EphemeralRange& range) {
+  const VisiblePosition& start = CreateVisiblePosition(range.StartPosition());
+  DCHECK(start.IsNotNull()) << range.StartPosition();
+  const Position& paragraph_start = StartOfParagraph(start).DeepEquivalent();
+  DCHECK(paragraph_start.IsNotNull()) << range.StartPosition();
+
+  const VisiblePosition& end = CreateVisiblePosition(range.EndPosition());
+  DCHECK(end.IsNotNull()) << range.EndPosition();
+  const Position& paragraph_end = EndOfParagraph(end).DeepEquivalent();
+  DCHECK(paragraph_end.IsNotNull()) << range.EndPosition();
+
+  // TODO(xiaochengh): There are some cases (crbug.com/640112) where we get
+  // |paragraphStart > paragraphEnd|, which is the reason we cannot directly
+  // return |EphemeralRange(paragraphStart, paragraphEnd)|. This is not
+  // desired, though. We should do more investigation to ensure that why
+  // |paragraphStart <= paragraphEnd| is violated.
+  const Position& result_start =
+      paragraph_start.IsNotNull() && paragraph_start <= range.StartPosition()
+          ? paragraph_start
+          : range.StartPosition();
+  const Position& result_end =
+      paragraph_end.IsNotNull() && paragraph_end >= range.EndPosition()
+          ? paragraph_end
+          : range.EndPosition();
+  return EphemeralRange(result_start, result_end);
+}
+
 // ---------
 
 VisiblePosition StartOfBlock(const VisiblePosition& visible_position,