Make NextWordPosition() to utilize TextOffsetMapping

This patch changes |NextWordPosition()| to utilize |TextOffsetMapping| to make
|NextWordPosition()| to work with LayoutNG.

This patch is a part of the patch[1].

[1] http://crrev.com/c/737981 Simplify word granularity handling

Bug: 778507, 810579

Change-Id: I7e196b0ee390d68b93f2494333554279d6fbd42d
Reviewed-on: https://chromium-review.googlesource.com/1004536
Commit-Queue: Yoshifumi Inoue <yosin@chromium.org>
Reviewed-by: Yoichi Osato <yoichio@chromium.org>
Reviewed-by: Xiaocheng Hu <xiaochengh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#550106}

third_party/blink/renderer/core/editing/visible_units_word.cc

@@ -31,7 +31,10 @@
 #include "third_party/blink/renderer/core/editing/visible_units.h"
 
 #include "third_party/blink/renderer/core/editing/editing_utilities.h"
+#include "third_party/blink/renderer/core/editing/ephemeral_range.h"
+#include "third_party/blink/renderer/core/editing/text_offset_mapping.h"
 #include "third_party/blink/renderer/core/editing/visible_position.h"
+#include "third_party/blink/renderer/core/layout/layout_block.h"
 #include "third_party/blink/renderer/platform/instrumentation/tracing/trace_event.h"
 #include "third_party/blink/renderer/platform/text/text_boundaries.h"
 
@@ -76,20 +79,25 @@ PositionTemplate<Strategy> EndOfWordAlgorithm(
   return NextBoundary(p, EndWordBoundary);
 }
 
-unsigned NextWordPositionBoundary(
-    const UChar* characters,
-    unsigned length,
-    unsigned offset,
-    BoundarySearchContextAvailability may_have_more_context,
-    bool& need_more_context) {
-  if (may_have_more_context &&
-      EndOfFirstWordBoundaryContext(characters + offset, length - offset) ==
-          static_cast<int>(length - offset)) {
-    need_more_context = true;
-    return length;
+PositionInFlatTree NextWordPositionInternal(
+    const PositionInFlatTree& position) {
+  PositionInFlatTree block_end_position;
+  for (const LayoutBlock* block =
+           &TextOffsetMapping::ComputeContainigBlock(position);
+       block; block = TextOffsetMapping::NextBlockFor(*block)) {
+    const TextOffsetMapping mapping(*block);
+    const String text = mapping.GetText();
+    const int offset =
+        block_end_position.IsNull() ? mapping.ComputeTextOffset(position) : 0;
+    const int word_end =
+        FindNextWordForward(text.Characters16(), text.length(), offset);
+    if (offset < word_end)
+      return mapping.GetPositionAfter(word_end);
+    block_end_position = mapping.GetRange().EndPosition();
   }
-  need_more_context = false;
-  return FindNextWordForward(characters, length, offset);
+  // TODO(yosin): Once we have a case, we should remove following |DCHECK()|.
+  DCHECK(block_end_position.IsNotNull()) << block_end_position;
+  return block_end_position;
 }
 
 unsigned PreviousWordPositionBoundary(
@@ -167,13 +175,32 @@ VisiblePositionInFlatTree EndOfWord(const VisiblePositionInFlatTree& position,
                                TextAffinity::kUpstreamIfPossible);
 }
 
+// ----
+// TODO(editing-dev): Because of word boundary can not be an upstream position,
+// we should make this function to return |PositionInFlatTree|.
+PositionInFlatTreeWithAffinity NextWordPosition(
+    const PositionInFlatTree& start) {
+  const PositionInFlatTree next = NextWordPositionInternal(start);
+  // Note: The word boundary can not be upstream position.
+  const PositionInFlatTreeWithAffinity adjusted =
+      AdjustForwardPositionToAvoidCrossingEditingBoundaries(
+          PositionInFlatTreeWithAffinity(next), start);
+  DCHECK_EQ(adjusted.Affinity(), TextAffinity::kDownstream);
+  return adjusted;
+}
+
+PositionWithAffinity NextWordPosition(const Position& start) {
+  const PositionInFlatTreeWithAffinity& next =
+      NextWordPosition(ToPositionInFlatTree(start));
+  return PositionWithAffinity(ToPositionInDOMTree(next.GetPosition()),
+                              next.Affinity());
+}
+
+// TODO(yosin): This function will be removed by replacing call sites to use
+// |Position| version. since there are only two call sites, one is in test.
 VisiblePosition NextWordPosition(const VisiblePosition& c) {
   DCHECK(c.IsValid()) << c;
-  VisiblePosition next =
-      CreateVisiblePosition(NextBoundary(c, NextWordPositionBoundary),
-                            TextAffinity::kUpstreamIfPossible);
-  return AdjustForwardPositionToAvoidCrossingEditingBoundaries(
-      next, c.DeepEquivalent());
+  return CreateVisiblePosition(NextWordPosition(c.DeepEquivalent()));
 }
 
 VisiblePosition PreviousWordPosition(const VisiblePosition& c) {

third_party/blink/renderer/core/editing/visible_units_word_test.cc

@@ -7,6 +7,7 @@
 #include "third_party/blink/renderer/core/editing/selection_template.h"
 #include "third_party/blink/renderer/core/editing/testing/editing_test_base.h"
 #include "third_party/blink/renderer/core/editing/visible_position.h"
+#include "third_party/blink/renderer/platform/testing/runtime_enabled_features_test_helpers.h"
 
 namespace blink {
 
@@ -60,6 +61,20 @@ class VisibleUnitsWordTest : public EditingTestBase {
   }
 };
 
+class ParameterizedVisibleUnitsWordTest
+    : public ::testing::WithParamInterface<bool>,
+      private ScopedLayoutNGForTest,
+      public VisibleUnitsWordTest {
+ protected:
+  ParameterizedVisibleUnitsWordTest() : ScopedLayoutNGForTest(GetParam()) {}
+
+  bool LayoutNGEnabled() const { return GetParam(); }
+};
+
+INSTANTIATE_TEST_CASE_P(All,
+                        ParameterizedVisibleUnitsWordTest,
+                        ::testing::Bool());
+
 TEST_F(VisibleUnitsWordTest, StartOfWordBasic) {
   EXPECT_EQ("<p> |(1) abc def</p>", DoStartOfWord("<p>| (1) abc def</p>"));
   EXPECT_EQ("<p> |(1) abc def</p>", DoStartOfWord("<p> |(1) abc def</p>"));
@@ -367,7 +382,7 @@ TEST_F(VisibleUnitsWordTest, EndOfWordTextSecurity) {
   EXPECT_EQ("abc<s>foo bar</s>baz|", DoEndOfWord("abc<s>foo bar</s>b|az"));
 }
 
-TEST_F(VisibleUnitsWordTest, NextWordBasic) {
+TEST_P(ParameterizedVisibleUnitsWordTest, NextWordBasic) {
   EXPECT_EQ("<p> (1|) abc def</p>", DoNextWord("<p>| (1) abc def</p>"));
   EXPECT_EQ("<p> (1|) abc def</p>", DoNextWord("<p> |(1) abc def</p>"));
   EXPECT_EQ("<p> (1|) abc def</p>", DoNextWord("<p> (|1) abc def</p>"));
@@ -384,12 +399,12 @@ TEST_F(VisibleUnitsWordTest, NextWordBasic) {
   EXPECT_EQ("<p> (1) abc def|</p>", DoNextWord("<p> (1) abc def</p>|"));
 }
 
-TEST_F(VisibleUnitsWordTest, NextWordCrossingBlock) {
+TEST_P(ParameterizedVisibleUnitsWordTest, NextWordCrossingBlock) {
   EXPECT_EQ("<p>abc|</p><p>def</p>", DoNextWord("<p>|abc</p><p>def</p>"));
   EXPECT_EQ("<p>abc</p><p>def|</p>", DoNextWord("<p>abc|</p><p>def</p>"));
 }
 
-TEST_F(VisibleUnitsWordTest, NextWordMixedEditability) {
+TEST_P(ParameterizedVisibleUnitsWordTest, NextWordMixedEditability) {
   EXPECT_EQ(
       "<p contenteditable>"
       "abc<b contenteditable=\"false\">def ghi</b>|jkl mno</p>",
@@ -412,7 +427,7 @@ TEST_F(VisibleUnitsWordTest, NextWordMixedEditability) {
                  "abc<b contenteditable=false>def ghi|</b>jkl mno</p>"));
 }
 
-TEST_F(VisibleUnitsWordTest, NextWordPunctuation) {
+TEST_P(ParameterizedVisibleUnitsWordTest, NextWordPunctuation) {
   EXPECT_EQ("abc|.def", DoNextWord("|abc.def"));
   EXPECT_EQ("abc|.def", DoNextWord("a|bc.def"));
   EXPECT_EQ("abc|.def", DoNextWord("ab|c.def"));
@@ -428,7 +443,7 @@ TEST_F(VisibleUnitsWordTest, NextWordPunctuation) {
   EXPECT_EQ("abc...def|", DoNextWord("abc...|def"));
 }
 
-TEST_F(VisibleUnitsWordTest, NextWordSkipTab) {
+TEST_P(ParameterizedVisibleUnitsWordTest, NextWordSkipTab) {
   InsertStyleElement("s { white-space: pre }");
   EXPECT_EQ("<p><s>\t</s>foo|</p>", DoNextWord("<p><s>\t|</s>foo</p>"));
 }