[Sh-Blink] Autocomplete first and last words.

Update user selection range so that first and last words are complete
words, otherwise TextFragmentFinder will not find a match.
For example, where '[' and ']' indicates user selection.
"samp[le text that user sel]ected"
will be changed to
"[sample text that user selected]"

Bug: 1129647
Change-Id: I5e2274b0e1ed0cc240fcea39ffcc369ab29ce171
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2424541
Commit-Queue: Gayane Petrosyan <gayane@chromium.org>
Reviewed-by: David Bokan <bokan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810591}

third_party/blink/renderer/core/page/scrolling/text_fragment_selector_generator.cc

@@ -182,6 +182,36 @@ void TextFragmentSelectorGenerator::BindTextFragmentSelectorProducer(
       selection_frame_->GetTaskRunner(blink::TaskType::kInternalDefault));
 }
 
+void TextFragmentSelectorGenerator::CompleteSelection() {
+  if (!selection_range_)
+    return;
+
+  EphemeralRangeInFlatTree ephemeral_range(selection_range_);
+  Node* start_container =
+      ephemeral_range.StartPosition().ComputeContainerNode();
+  Node* end_container = ephemeral_range.EndPosition().ComputeContainerNode();
+
+  String start_text = start_container->textContent();
+  int selection_start_pos =
+      ephemeral_range.StartPosition().ComputeOffsetInContainerNode();
+  start_text.Ensure16Bit();
+  int word_start = FindWordStartBoundary(
+      start_text.Characters16(), start_text.length(), selection_start_pos);
+
+  String end_text = end_container->textContent();
+  int selection_end_pos =
+      ephemeral_range.EndPosition().ComputeOffsetInContainerNode();
+  end_text.Ensure16Bit();
+  int word_end = FindWordEndBoundary(end_text.Characters16(), end_text.length(),
+                                     selection_end_pos);
+  if (word_start != selection_start_pos || word_end != selection_end_pos) {
+    selection_range_ =
+        MakeGarbageCollected<Range>(selection_range_->OwnerDocument(),
+                                    Position(start_container, word_start),
+                                    Position(end_container, word_end));
+  }
+}
+
 void TextFragmentSelectorGenerator::GenerateSelector(
     GenerateSelectorCallback callback) {
   DCHECK(selection_range_);
@@ -195,6 +225,7 @@ void TextFragmentSelectorGenerator::GenerateSelector(
   num_prefix_words_ = 0;
   num_suffix_words_ = 0;
 
+  CompleteSelection();
   GenerateSelectorCandidate();
 }
 
@@ -283,13 +314,14 @@ void TextFragmentSelectorGenerator::GenerateExactSelector() {
   DCHECK_EQ(kNeedsNewCandidate, state_);
 
   EphemeralRangeInFlatTree ephemeral_range(selection_range_);
+  Node* start_container =
+      ephemeral_range.StartPosition().ComputeContainerNode();
+  Node* end_container = ephemeral_range.EndPosition().ComputeContainerNode();
 
   Node& start_first_block_ancestor =
-      FindBuffer::GetFirstBlockLevelAncestorInclusive(
-          *ephemeral_range.StartPosition().ComputeContainerNode());
+      FindBuffer::GetFirstBlockLevelAncestorInclusive(*start_container);
   Node& end_first_block_ancestor =
-      FindBuffer::GetFirstBlockLevelAncestorInclusive(
-          *ephemeral_range.EndPosition().ComputeContainerNode());
+      FindBuffer::GetFirstBlockLevelAncestorInclusive(*end_container);
 
   // If not in same node, should use ranges.
   if (!start_first_block_ancestor.isSameNode(&end_first_block_ancestor)) {
@@ -301,8 +333,6 @@ void TextFragmentSelectorGenerator::GenerateExactSelector() {
   // by a block. Example: <div>start of the selection <div> sub block </div>end
   // of the selection</div>.
 
-  // TODO(gayane): Move selection start and end to contain full words.
-
   String selected_text = PlainText(ephemeral_range);
 
   // If too long should use ranges.
@@ -397,11 +427,7 @@ void TextFragmentSelectorGenerator::ExtendRangeSelector() {
 void TextFragmentSelectorGenerator::ExtendContext() {
   DCHECK_EQ(kContext, step_);
   DCHECK_EQ(kNeedsNewCandidate, state_);
-
-  // TODO(gayane): Change this to DCHECK after |ExtendRangeSelector| is
-  // implemented.
-  if (!selector_)
-    return;
+  DCHECK(selector_);
 
   // Give up if context is already too long.
   if (num_prefix_words_ == kMaxContextWords ||

third_party/blink/renderer/core/page/scrolling/text_fragment_selector_generator.h

@@ -41,6 +41,9 @@ class CORE_EXPORT TextFragmentSelectorGenerator final
   void UpdateSelection(LocalFrame* selection_frame,
                        const EphemeralRangeInFlatTree& selection_range);
 
+  // Extend the selection from start and end to contain full words.
+  void CompleteSelection();
+
   // blink::mojom::blink::TextFragmentSelectorProducer interface
   // Generates selector for current selection.
   void GenerateSelector(GenerateSelectorCallback callback) override;

third_party/blink/renderer/core/page/scrolling/text_fragment_selector_generator_test.cc

@@ -547,6 +547,47 @@ text_text_text_text_text_text_text_text_text_and_last_text",
   GenerateAndVerifySelector(selected_start, selected_end, "");
 }
 
+// Selection should be autocompleted to contain full words.
+TEST_F(TextFragmentSelectorGeneratorTest, WordLimit) {
+  SimRequest request("https://example.com/test.html", "text/html");
+  LoadURL("https://example.com/test.html");
+  request.Complete(R"HTML(
+    <!DOCTYPE html>
+    <div>Test page</div>
+    <p id='first'>First paragraph text that is longer than 20 chars</p>
+  )HTML");
+  Node* first_paragraph = GetDocument().getElementById("first")->firstChild();
+  const auto& selected_start = Position(first_paragraph, 7);
+  const auto& selected_end = Position(first_paragraph, 33);
+  ASSERT_EQ("aragraph text that is long",
+            PlainText(EphemeralRange(selected_start, selected_end)));
+
+  GenerateAndVerifySelector(selected_start, selected_end,
+                            "paragraph%20text%20that%20is%20longer");
+}
+
+// Selection should be autocompleted to contain full words. The autocompletion
+// should work with extra spaces.
+TEST_F(TextFragmentSelectorGeneratorTest, WordLimit_ExtraSpaces) {
+  SimRequest request("https://example.com/test.html", "text/html");
+  LoadURL("https://example.com/test.html");
+  request.Complete(R"HTML(
+    <!DOCTYPE html>
+    <div>Test page</div>
+    <p id='first'>First
+    paragraph text
+    that is longer than 20 chars</p>
+  )HTML");
+  Node* first_paragraph = GetDocument().getElementById("first")->firstChild();
+  const auto& selected_start = Position(first_paragraph, 11);
+  const auto& selected_end = Position(first_paragraph, 41);
+  ASSERT_EQ("aragraph text that is long",
+            PlainText(EphemeralRange(selected_start, selected_end)));
+
+  GenerateAndVerifySelector(selected_start, selected_end,
+                            "paragraph%20text%20that%20is%20longer");
+}
+
 // Basic test case for |GetNextTextBlock|.
 TEST_F(TextFragmentSelectorGeneratorTest, GetPreviousTextBlock) {
   SimRequest request("https://example.com/test.html", "text/html");