[EditContext] Add UseCounter for updateText and updateSelection

This CL adds use counters to analyze the impact of implementing the
change proposed in [1]. Following counters are added:
1. kEditContextUpdateTextRangePrecedesOrOverlapsSelection: Tracks when
updateText is called and the update range precedes or overlaps the
selection.
2. kEditContextUpdateTextRangePrecedesCompositionRange: Tracks when
updateText is called and the update range precedes the composition
range during an active composition.
3. kEditContextUpdateTextRangeOverlapsCompositionRange: Tracks when
updateText is called and the update range overlaps with the composition
range during an active composition.
4. kEditContextUpdateSelectionDuringActiveComposition: Tracks when
updateSelection is called during an active composition.

[1] w3c/edit-context#115

These counters will help us understand how frequently these behaviors
occur before making changes to the spec implementation.

Bug: 379170477
Change-Id: I8043fdb6161137f79d8eaa3336b90d93ca25042c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6549358
Reviewed-by: Dan Clark <daniec@microsoft.com>
Commit-Queue: Ashish Kumar <ashishkum@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#1462602}

Author: ashishkum-ms

third_party/blink/public/mojom/use_counter/metrics/web_feature.mojom

@@ -4888,6 +4888,10 @@ enum WebFeature {
   kPopoverShown = 5579,
   kInputParsedParentOptionOrOptgroup = 5580,
   kNavigatorUAData_toJSON = 5581,
+  kEditContextUpdateTextRangePrecedesOrOverlapsSelection = 5582,
+  kEditContextUpdateTextRangePrecedesCompositionRange = 5583,
+  kEditContextUpdateTextRangeOverlapsCompositionRange = 5584,
+  kEditContextUpdateSelectionDuringActiveComposition = 5585,
 
   // Add new features immediately above this line. Don't change assigned
   // numbers of any item, and don't reuse removed slots. Also don't add extra

third_party/blink/renderer/core/editing/ime/edit_context.cc

@@ -243,7 +243,16 @@ void EditContext::updateSelection(uint32_t start,
   TRACE_EVENT2("ime", "EditContext::updateSelection", "start",
                std::to_string(start), "end", std::to_string(end));
 
-  SetSelection(std::min(start, text_.length()), std::min(end, text_.length()));
+  uint32_t bound_start = std::min(start, text_.length());
+  uint32_t bound_end = std::min(end, text_.length());
+  if (has_composition_ &&
+      (bound_start != selection_start_ || bound_end != selection_end_)) {
+    UseCounter::Count(
+        GetExecutionContext(),
+        WebFeature::kEditContextUpdateSelectionDuringActiveComposition);
+  }
+
+  SetSelection(bound_start, bound_end);
   if (!has_composition_)
     return;
 
@@ -309,6 +318,29 @@ void EditContext::updateText(uint32_t start,
   }
   end = std::min(end, text_.length());
   start = std::min(start, end);
+
+  if (OrderedSelectionEnd() > start) {
+    UseCounter::Count(
+        GetExecutionContext(),
+        WebFeature::kEditContextUpdateTextRangePrecedesOrOverlapsSelection);
+  }
+
+  if (has_composition_ && composition_range_end_ > start) {
+    if (composition_range_start_ >= end) {
+      // Example:
+      // Composition range: [3, 6], Update range: [1, 2]
+      UseCounter::Count(
+          GetExecutionContext(),
+          WebFeature::kEditContextUpdateTextRangePrecedesCompositionRange);
+    } else {
+      // Example:
+      // Composition range: [3, 6], Update range: [4, 7]
+      UseCounter::Count(
+          GetExecutionContext(),
+          WebFeature::kEditContextUpdateTextRangeOverlapsCompositionRange);
+    }
+  }
+
   text_ = text_.Substring(0, start) + new_text + text_.Substring(end);
 }
 

third_party/blink/web_tests/editing/input/edit-context.html

@@ -759,6 +759,83 @@
 
   test.remove();
 }, 'Testing UseCounter for textformatupdate event.');
+
+test(function(){
+  const kEditContextUpdateTextRangePrecedesOrOverlapsSelection = 5582;
+  const kEditContextUpdateTextRangePrecedesCompositionRange = 5583;
+  const kEditContextUpdateTextRangeOverlapsCompositionRange = 5584;
+  internals.clearUseCounter(document, kEditContextUpdateTextRangePrecedesOrOverlapsSelection);
+  internals.clearUseCounter(document, kEditContextUpdateTextRangePrecedesCompositionRange);
+  internals.clearUseCounter(document, kEditContextUpdateTextRangeOverlapsCompositionRange);
+
+  const text = "ABCD";
+  const editContext = new EditContext({text: text, selectionStart: 1, selectionEnd: 1});
+  const test = document.createElement("div");
+  test.textContent = text;
+  document.body.appendChild(test);
+  test.editContext = editContext;
+  test.focus();
+
+  assert_false(internals.isUseCounted(document, kEditContextUpdateTextRangePrecedesOrOverlapsSelection));
+
+  // UpdateText range is outside the selection range.
+  editContext.updateText(4, 4, "1");
+  assert_false(internals.isUseCounted(document, kEditContextUpdateTextRangePrecedesOrOverlapsSelection));
+
+  // UpdateText range is less than selection range.
+  editContext.updateText(0, 0, "2");
+  assert_true(internals.isUseCounted(document, kEditContextUpdateTextRangePrecedesOrOverlapsSelection));
+
+  editContext.updateSelection(1, 1);
+  textInputController.setComposition("foo");
+  assert_false(internals.isUseCounted(document, kEditContextUpdateTextRangePrecedesCompositionRange));
+  assert_false(internals.isUseCounted(document, kEditContextUpdateTextRangeOverlapsCompositionRange));
+
+  // UpdeText range is outside the composition range.
+  editContext.updateText(5, 5, "3");
+  assert_false(internals.isUseCounted(document, kEditContextUpdateTextRangePrecedesCompositionRange));
+  assert_false(internals.isUseCounted(document, kEditContextUpdateTextRangeOverlapsCompositionRange));
+
+  // UpdateText range is less than composition range but does not overlap.
+  editContext.updateText(0, 0, "4");
+  assert_true(internals.isUseCounted(document, kEditContextUpdateTextRangePrecedesCompositionRange));
+  assert_false(internals.isUseCounted(document, kEditContextUpdateTextRangeOverlapsCompositionRange));
+
+  // UpdateText range overlaps with composition range.
+  editContext.updateText(0, 3, "5");
+  assert_true(internals.isUseCounted(document, kEditContextUpdateTextRangeOverlapsCompositionRange));
+
+  test.remove();
+}, 'Testing UseCounter for updateText based on update range and selection/composition range.');
+
+test(function(){
+  const kEditContextUpdateSelectionDuringActiveComposition = 5585;
+  internals.clearUseCounter(document, kEditContextUpdateSelectionDuringActiveComposition);
+
+  const text = "ABCD";
+  const editContext = new EditContext({text: text, selectionStart: 0, selectionEnd: 0});
+  const test = document.createElement("div");
+  test.textContent = text;
+  document.body.appendChild(test);
+  test.editContext = editContext;
+  test.focus();
+
+  // Tracks when selection is updated to new value while a composition is active.
+  assert_false(internals.isUseCounted(document, kEditContextUpdateSelectionDuringActiveComposition));
+  editContext.updateSelection(1, 1);
+  assert_false(internals.isUseCounted(document, kEditContextUpdateSelectionDuringActiveComposition));
+
+  textInputController.setComposition("foo");
+  assert_equals(editContext.selectionStart, 4);
+  assert_equals(editContext.selectionEnd, 4);
+  editContext.updateSelection(4, 4);
+  assert_false(internals.isUseCounted(document, kEditContextUpdateSelectionDuringActiveComposition));
+
+  editContext.updateSelection(2, 2);
+  assert_true(internals.isUseCounted(document, kEditContextUpdateSelectionDuringActiveComposition));
+
+  test.remove();
+}, 'Testing UseCounter for updateSelection during an active composition.');
 </script>
 </body>
 </html>

tools/metrics/histograms/metadata/blink/enums.xml

@@ -6209,6 +6209,11 @@ Called by update_use_counter_feature_enum.py.-->
   <int value="5579" label="PopoverShown"/>
   <int value="5580" label="InputParsedParentOptionOrOptgroup"/>
   <int value="5581" label="NavigatorUAData_toJSON"/>
+  <int value="5582"
+      label="EditContextUpdateTextRangePrecedesOrOverlapsSelection"/>
+  <int value="5583" label="EditContextUpdateTextRangePrecedesCompositionRange"/>
+  <int value="5584" label="EditContextUpdateTextRangeOverlapsCompositionRange"/>
+  <int value="5585" label="EditContextUpdateSelectionDuringActiveComposition"/>
 </enum>
 
 <!-- LINT.ThenChange(//third_party/blink/public/mojom/use_counter/metrics/web_feature.mojom:WebFeature) -->