Avoid duplicate functions/code in core/editing: computeDistance

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

Index: third_party/WebKit/Source/core/editing/EditingUtilities.cpp
diff --git a/third_party/WebKit/Source/core/editing/EditingUtilities.cpp b/third_party/WebKit/Source/core/editing/EditingUtilities.cpp
index 13539b5bda7fc20fc738591c0044097ff6190ac3..15fcc2f0e3aaf15065c6170b1e2e00f8ad424af3 100644
--- a/third_party/WebKit/Source/core/editing/EditingUtilities.cpp
+++ b/third_party/WebKit/Source/core/editing/EditingUtilities.cpp
@@ -2059,6 +2059,32 @@ bool isTextSecurityNode(const Node* node) {
          node->layoutObject()->style()->textSecurity() != TSNONE;
 }
 
+// If current position is at grapheme boundary, return 0; otherwise, return the
+// distance to its nearest left grapheme boundary.
+size_t computeDistanceToLeftGraphemeBoundary(const Position& position) {
+  const Position& adjustedPosition = previousPositionOf(
+      nextPositionOf(position, PositionMoveType::GraphemeCluster),
+      PositionMoveType::GraphemeCluster);
+  DCHECK_EQ(position.anchorNode(), adjustedPosition.anchorNode());
+  DCHECK_GE(position.computeOffsetInContainerNode(),
+            adjustedPosition.computeOffsetInContainerNode());
+  return static_cast<size_t>(position.computeOffsetInContainerNode() -
+                             adjustedPosition.computeOffsetInContainerNode());
+}
+
+// If current position is at grapheme boundary, return 0; otherwise, return the
+// distance to its nearest right grapheme boundary.
+size_t computeDistanceToRightGraphemeBoundary(const Position& position) {
+  const Position& adjustedPosition = nextPositionOf(
+      previousPositionOf(position, PositionMoveType::GraphemeCluster),
+      PositionMoveType::GraphemeCluster);
+  DCHECK_EQ(position.anchorNode(), adjustedPosition.anchorNode());
+  DCHECK_GE(adjustedPosition.computeOffsetInContainerNode(),
+            position.computeOffsetInContainerNode());
+  return static_cast<size_t>(adjustedPosition.computeOffsetInContainerNode() -
+                             position.computeOffsetInContainerNode());
+}
+
 const StaticRangeVector* targetRangesForInputEvent(const Node& node) {
   // TODO(xiaochengh): The use of updateStyleAndLayoutIgnorePendingStylesheets
   // needs to be audited. see http://crbug.com/590369 for more details.