[Shape Detection] Make DetectedText interface serializable.

This CL makes sure DetectedText interface is serializable so that
DetectedText can easily be transfered from workers.

Change-Id: Ic5ac034ae4f472c34ae75ec001cfda5af97cf6a9
Reviewed-on: https://chromium-review.googlesource.com/1243023
Commit-Queue: François Beaufort <beaufort.francois@gmail.com>
Reviewed-by: Miguel Casas <mcasas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#594452}

third_party/WebKit/LayoutTests/webexposed/global-interface-listing-expected.txt

@@ -1438,6 +1438,7 @@ interface DetectedText
     getter cornerPoints
     getter rawValue
     method constructor
+    method toJSON
 interface DeviceMotionEvent : Event
     attribute @@toStringTag
     getter acceleration

third_party/blink/renderer/modules/shapedetection/detected_text.cc

@@ -4,6 +4,7 @@
 
 #include "third_party/blink/renderer/modules/shapedetection/detected_text.h"
 
+#include "third_party/blink/renderer/bindings/core/v8/v8_object_builder.h"
 #include "third_party/blink/renderer/core/geometry/dom_rect.h"
 
 namespace blink {
@@ -39,6 +40,21 @@ DetectedText::DetectedText(String raw_value,
       bounding_box_(bounding_box),
       corner_points_(corner_points) {}
 
+ScriptValue DetectedText::toJSONForBinding(ScriptState* script_state) const {
+  V8ObjectBuilder result(script_state);
+  result.AddString("rawValue", rawValue());
+  result.Add("boundingBox", boundingBox()->toJSONForBinding(script_state));
+  Vector<ScriptValue> corner_points;
+  for (const auto& corner_point : corner_points_) {
+    V8ObjectBuilder builder(script_state);
+    builder.AddNumber("x", corner_point.x());
+    builder.AddNumber("y", corner_point.y());
+    corner_points.push_back(builder.GetScriptValue());
+  }
+  result.Add("cornerPoints", corner_points);
+  return result.GetScriptValue();
+}
+
 void DetectedText::Trace(blink::Visitor* visitor) {
   visitor->Trace(bounding_box_);
   visitor->Trace(corner_points_);

third_party/blink/renderer/modules/shapedetection/detected_text.h

@@ -5,6 +5,7 @@
 #ifndef THIRD_PARTY_BLINK_RENDERER_MODULES_SHAPEDETECTION_DETECTED_TEXT_H_
 #define THIRD_PARTY_BLINK_RENDERER_MODULES_SHAPEDETECTION_DETECTED_TEXT_H_
 
+#include "third_party/blink/renderer/bindings/core/v8/script_value.h"
 #include "third_party/blink/renderer/modules/imagecapture/point_2d.h"
 #include "third_party/blink/renderer/modules/modules_export.h"
 #include "third_party/blink/renderer/platform/bindings/script_wrappable.h"
@@ -24,6 +25,8 @@ class MODULES_EXPORT DetectedText final : public ScriptWrappable {
   const String& rawValue() const;
   DOMRectReadOnly* boundingBox() const;
   const HeapVector<Point2D>& cornerPoints() const;
+
+  ScriptValue toJSONForBinding(ScriptState*) const;
   void Trace(blink::Visitor*) override;
 
  private:

third_party/blink/renderer/modules/shapedetection/detected_text.idl

@@ -13,4 +13,6 @@
     // 4 corner points in clockwise direction starting with top-left. Due to
     // possible perspective distortions, this is not necessarily a rectangle.
     [SameObject] readonly attribute FrozenArray<Point2D> cornerPoints;
+
+    serializer = { attribute };
 };