address comments

Author: mdebbar

lib/web_ui/lib/src/engine/text/canvas_paragraph.dart

@@ -30,6 +30,7 @@ class CanvasParagraph implements EngineParagraph {
   /// The number of placeholders in this paragraph.
   final int placeholderCount;
 
+  // Defaulting to -1 for non-laid-out paragraphs like the native engine does.
   @override
   double width = -1.0;
 

lib/web_ui/lib/src/engine/text/paragraph.dart

@@ -245,6 +245,7 @@ class DomParagraph implements EngineParagraph {
 
   bool get _hasLineMetrics => _measurementResult?.lines != null;
 
+  // Defaulting to -1 for non-laid-out paragraphs like the native engine does.
   @override
   double get width => _measurementResult?.width ?? -1;
 

lib/web_ui/test/text/canvas_paragraph_builder_test.dart

@@ -17,6 +17,9 @@ void testMain() {
     WebExperiments.ensureInitialized();
   });
 
+  // TODO(mdebbar): Add checks for the output of `toDomElement()` in all the
+  //                tests below.
+
   test('Builds a text-only canvas paragraph', () {
     final EngineParagraphStyle style = EngineParagraphStyle(fontSize: 13.0);
     final CanvasParagraphBuilder builder = CanvasParagraphBuilder(style);