Expose subroutines of ComputeInlinePosition

This patch exposes two subroutines of ComputeInlineBoxPosition:
- ComputeInlineAdjustedPosition
- ComputeInlineBoxPositionForInlineAdjustedPosition

After this patch, we can start converting callers of
ComputeInlineBoxPosition with the following pattern:

DoSomeBusiness(position) {
  adjusted = ComputeInlineAdjustedPosition(position);
  if (/* adjusted is laid out with LayoutNG */)
    return NGAlternativeImplementation(adjusted);
  legacy_box_position =
      ComputeInlineBoxPositionForInlineAdjustedPosition(adjusted);
  DoLegacyBusiness(legacy_box_position);
}

Bug: 771398
Change-Id: Iea01925e7ef986c5b00dd5b6e7172f7065c8df9e
Reviewed-on: https://chromium-review.googlesource.com/792453Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521274}

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

@@ -299,7 +299,7 @@ InlineBoxPosition ComputeInlineBoxPositionForAtomicInline(
 }
 
 template <typename Strategy>
-PositionWithAffinityTemplate<Strategy> ComputeInlineAdjustedPosition(
+PositionWithAffinityTemplate<Strategy> ComputeInlineAdjustedPositionAlgorithm(
     const PositionWithAffinityTemplate<Strategy>&);
 
 template <typename Strategy>
@@ -312,8 +312,9 @@ PositionWithAffinityTemplate<Strategy> AdjustBlockFlowPositionToInline(
   const PositionTemplate<Strategy>& downstream_equivalent =
       DownstreamIgnoringEditingBoundaries(position);
   if (downstream_equivalent != position) {
-    return ComputeInlineAdjustedPosition(PositionWithAffinityTemplate<Strategy>(
-        downstream_equivalent, TextAffinity::kUpstream));
+    return ComputeInlineAdjustedPositionAlgorithm(
+        PositionWithAffinityTemplate<Strategy>(downstream_equivalent,
+                                               TextAffinity::kUpstream));
   }
   const PositionTemplate<Strategy>& upstream_equivalent =
       UpstreamIgnoringEditingBoundaries(position);
@@ -321,14 +322,13 @@ PositionWithAffinityTemplate<Strategy> AdjustBlockFlowPositionToInline(
       DownstreamIgnoringEditingBoundaries(upstream_equivalent) == position)
     return PositionWithAffinityTemplate<Strategy>();
 
-  return ComputeInlineAdjustedPosition(PositionWithAffinityTemplate<Strategy>(
-      upstream_equivalent, TextAffinity::kUpstream));
+  return ComputeInlineAdjustedPositionAlgorithm(
+      PositionWithAffinityTemplate<Strategy>(upstream_equivalent,
+                                             TextAffinity::kUpstream));
 }
 
-// TODO(xiaochengh): Expose this function for current callers of
-// ComputeInlineBoxPosition() for deciding to use legacy or NG implementation.
 template <typename Strategy>
-PositionWithAffinityTemplate<Strategy> ComputeInlineAdjustedPosition(
+PositionWithAffinityTemplate<Strategy> ComputeInlineAdjustedPositionAlgorithm(
     const PositionWithAffinityTemplate<Strategy>& position) {
   const LayoutObject& layout_object =
       GetLayoutObjectSkippingShadowRoot(position.GetPosition());
@@ -350,9 +350,8 @@ PositionWithAffinityTemplate<Strategy> ComputeInlineAdjustedPosition(
   return AdjustBlockFlowPositionToInline(position.GetPosition());
 }
 
-// TODO(xiaochengh): Expose this function for code depending on legacy layout.
 template <typename Strategy>
-InlineBoxPosition ComputeInlineBoxPositionForInlineAdjustedPosition(
+InlineBoxPosition ComputeInlineBoxPositionForInlineAdjustedPositionAlgorithm(
     const PositionWithAffinityTemplate<Strategy>& adjusted,
     TextDirection primary_direction) {
   const PositionTemplate<Strategy>& position = adjusted.GetPosition();
@@ -372,6 +371,13 @@ InlineBoxPosition ComputeInlineBoxPositionForInlineAdjustedPosition(
                                                  primary_direction);
 }
 
+template <typename Strategy>
+InlineBoxPosition ComputeInlineBoxPositionForInlineAdjustedPositionAlgorithm(
+    const PositionWithAffinityTemplate<Strategy>& position) {
+  return ComputeInlineBoxPositionForInlineAdjustedPositionAlgorithm(
+      position, PrimaryDirectionOf(*position.AnchorNode()));
+}
+
 template <typename Strategy>
 InlineBoxPosition ComputeInlineBoxPositionTemplate(
     const PositionWithAffinityTemplate<Strategy>& position,
@@ -424,4 +430,45 @@ InlineBoxPosition ComputeInlineBoxPosition(
       position, primary_direction);
 }
 
+PositionWithAffinity ComputeInlineAdjustedPosition(
+    const PositionWithAffinity& position) {
+  return ComputeInlineAdjustedPositionAlgorithm(position);
+}
+
+PositionInFlatTreeWithAffinity ComputeInlineAdjustedPosition(
+    const PositionInFlatTreeWithAffinity& position) {
+  return ComputeInlineAdjustedPositionAlgorithm(position);
+}
+
+PositionWithAffinity ComputeInlineAdjustedPosition(
+    const VisiblePosition& position) {
+  DCHECK(position.IsValid()) << position;
+  return ComputeInlineAdjustedPositionAlgorithm(
+      position.ToPositionWithAffinity());
+}
+
+InlineBoxPosition ComputeInlineBoxPositionForInlineAdjustedPosition(
+    const PositionWithAffinity& position) {
+  return ComputeInlineBoxPositionForInlineAdjustedPositionAlgorithm(position);
+}
+
+InlineBoxPosition ComputeInlineBoxPositionForInlineAdjustedPosition(
+    const PositionInFlatTreeWithAffinity& position) {
+  return ComputeInlineBoxPositionForInlineAdjustedPositionAlgorithm(position);
+}
+
+InlineBoxPosition ComputeInlineBoxPositionForInlineAdjustedPosition(
+    const PositionWithAffinity& position,
+    TextDirection primary_direction) {
+  return ComputeInlineBoxPositionForInlineAdjustedPositionAlgorithm(
+      position, primary_direction);
+}
+
+InlineBoxPosition ComputeInlineBoxPositionForInlineAdjustedPosition(
+    const PositionInFlatTreeWithAffinity& position,
+    TextDirection primary_direction) {
+  return ComputeInlineBoxPositionForInlineAdjustedPositionAlgorithm(
+      position, primary_direction);
+}
+
 }  // namespace blink

third_party/WebKit/Source/core/editing/InlineBoxPosition.h

@@ -76,6 +76,22 @@ ComputeInlineBoxPosition(const PositionInFlatTreeWithAffinity&,
                          TextDirection primary_direction);
 CORE_EXPORT InlineBoxPosition ComputeInlineBoxPosition(const VisiblePosition&);
 
+PositionWithAffinity ComputeInlineAdjustedPosition(const PositionWithAffinity&);
+PositionInFlatTreeWithAffinity ComputeInlineAdjustedPosition(
+    const PositionInFlatTreeWithAffinity&);
+PositionWithAffinity ComputeInlineAdjustedPosition(const VisiblePosition&);
+
+InlineBoxPosition ComputeInlineBoxPositionForInlineAdjustedPosition(
+    const PositionWithAffinity&);
+InlineBoxPosition ComputeInlineBoxPositionForInlineAdjustedPosition(
+    const PositionWithAffinity&,
+    TextDirection primary_direction);
+InlineBoxPosition ComputeInlineBoxPositionForInlineAdjustedPosition(
+    const PositionInFlatTreeWithAffinity&);
+InlineBoxPosition ComputeInlineBoxPositionForInlineAdjustedPosition(
+    const PositionInFlatTreeWithAffinity&,
+    TextDirection primary_direction);
+
 // The print for |InlineBoxPosition| is available only for testing
 // in "webkit_unit_tests", and implemented in
 // "core/editing/InlineBoxPositionTest.cpp".