Introduce Find{Left,Right}BidiRun() and utilize in AdjustInlineBoxPositionForTextDirection()

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 0fe37bfec988ce5ee355ab3af0f81238c6e28496..d325380239b137b4c7a2f5ed33280e9a9ba38424 100644
--- a/third_party/WebKit/Source/core/editing/VisibleUnits.cpp
+++ b/third_party/WebKit/Source/core/editing/VisibleUnits.cpp
@@ -893,10 +893,8 @@ static InlineBoxPosition AdjustInlineBoxPositionForTextDirection(
         return InlineBoxPosition(inline_box, caret_offset);
 
       level = next_box->BidiLevel();
-      InlineBox* prev_box = inline_box;
-      do {
-        prev_box = prev_box->PrevLeafChild();
-      } while (prev_box && prev_box->BidiLevel() > level);
+      InlineBox* const prev_box =
+          InlineBoxTraversal::FindLeftBidiRun(*inline_box, level);
 
       // For example, abc FED 123 ^ CBA
       if (prev_box && prev_box->BidiLevel() == level)
@@ -912,10 +910,8 @@ static InlineBoxPosition AdjustInlineBoxPositionForTextDirection(
       return InlineBoxPosition(inline_box, caret_offset);
 
     level = inline_box->PrevLeafChild()->BidiLevel();
-    InlineBox* next_box = inline_box;
-    do {
-      next_box = next_box->NextLeafChild();
-    } while (next_box && next_box->BidiLevel() > level);
+    InlineBox* const next_box =
+        InlineBoxTraversal::FindRightBidiRun(*inline_box, level);
 
     if (next_box && next_box->BidiLevel() == level)
       return InlineBoxPosition(inline_box, caret_offset);