Converts drag-in-iframe.html to utilize w3c test harness

Because of "drag-in-iframe.html" doesn't require pixel comparison, this patch
converts "drag-in-iframe.html" to utilize w3c test harness with introducing
|internals.getDragCaret()| to check position of drag caret in test scripts, for
ease of maintenance.

Note: This patch helps to utilize --enable-display-compositor-pixel-dump.

Bug: 891427
Change-Id: Ie1ae56ac971271bccd6109a5044d25b433620f92
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1552397
Commit-Queue: Yoshifumi Inoue <yosin@chromium.org>
Auto-Submit: Yoshifumi Inoue <yosin@chromium.org>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#648082}

third_party/blink/renderer/core/editing/drag_caret.h

@@ -62,7 +62,7 @@ class DragCaret final : public GarbageCollectedFinalized<DragCaret>,
   bool IsContentRichlyEditable() const;
 
   bool HasCaret() const { return position_.IsNotNull(); }
-  const PositionWithAffinity& CaretPosition() { return position_; }
+  const PositionWithAffinity& CaretPosition() const { return position_; }
   void SetCaretPosition(const PositionWithAffinity&);
   void Clear() { SetCaretPosition(PositionWithAffinity()); }
 

third_party/blink/renderer/core/testing/internals.cc

@@ -58,6 +58,7 @@
 #include "third_party/blink/renderer/core/dom/shadow_root_v0.h"
 #include "third_party/blink/renderer/core/dom/static_node_list.h"
 #include "third_party/blink/renderer/core/dom/tree_scope.h"
+#include "third_party/blink/renderer/core/editing/drag_caret.h"
 #include "third_party/blink/renderer/core/editing/editor.h"
 #include "third_party/blink/renderer/core/editing/ephemeral_range.h"
 #include "third_party/blink/renderer/core/editing/frame_selection.h"
@@ -2898,6 +2899,17 @@ void Internals::forceReload(bool bypass_cache) {
                                   : WebFrameLoadType::kReload);
 }
 
+StaticSelection* Internals::getDragCaret() {
+  SelectionInDOMTree::Builder builder;
+  if (GetFrame()) {
+    const DragCaret& caret = GetFrame()->GetPage()->GetDragCaret();
+    const PositionWithAffinity& position = caret.CaretPosition();
+    if (position.GetDocument() == GetFrame()->GetDocument())
+      builder.Collapse(caret.CaretPosition());
+  }
+  return StaticSelection::FromSelectionInDOMTree(builder.Build());
+}
+
 StaticSelection* Internals::getSelectionInFlatTree(
     DOMWindow* window,
     ExceptionState& exception_state) {

third_party/blink/renderer/core/testing/internals.h

@@ -449,6 +449,7 @@ class Internals final : public ScriptWrappable {
   int selectPopupItemStyleFontHeight(Node*, int);
   void resetTypeAheadSession(HTMLSelectElement*);
 
+  StaticSelection* getDragCaret();
   StaticSelection* getSelectionInFlatTree(DOMWindow*, ExceptionState&);
   Node* visibleSelectionAnchorNode();
   unsigned visibleSelectionAnchorOffset();

third_party/blink/renderer/core/testing/internals.idl

@@ -284,6 +284,7 @@
     long selectPopupItemStyleFontHeight(Node select, long itemIndex);
     void resetTypeAheadSession(HTMLSelectElement select);
 
+    StaticSelection getDragCaret();
     [RaisesException] StaticSelection getSelectionInFlatTree(Window window);
     // TODO(editing-dev): We should change |visibleSelection*| to
     // |StaticSelection|.

third_party/blink/renderer/core/testing/static_selection.cc

@@ -8,18 +8,34 @@
 
 namespace blink {
 
+// static
+StaticSelection* StaticSelection::FromSelectionInDOMTree(
+    const SelectionInDOMTree& selection) {
+  return MakeGarbageCollected<StaticSelection>(selection);
+}
+
 // static
 StaticSelection* StaticSelection::FromSelectionInFlatTree(
     const SelectionInFlatTree& seleciton) {
   return MakeGarbageCollected<StaticSelection>(seleciton);
 }
 
+StaticSelection::StaticSelection(const SelectionInDOMTree& selection)
+    : anchor_node_(selection.Base().ComputeContainerNode()),
+      anchor_offset_(selection.Base().ComputeOffsetInContainerNode()),
+      focus_node_(selection.Extent().ComputeContainerNode()),
+      focus_offset_(selection.Extent().ComputeOffsetInContainerNode()) {}
+
 StaticSelection::StaticSelection(const SelectionInFlatTree& seleciton)
     : anchor_node_(seleciton.Base().ComputeContainerNode()),
       anchor_offset_(seleciton.Base().ComputeOffsetInContainerNode()),
       focus_node_(seleciton.Extent().ComputeContainerNode()),
       focus_offset_(seleciton.Extent().ComputeOffsetInContainerNode()) {}
 
+bool StaticSelection::isCollapsed() const {
+  return anchor_node_ == focus_node_ && anchor_offset_ == focus_offset_;
+}
+
 void StaticSelection::Trace(blink::Visitor* visitor) {
   visitor->Trace(anchor_node_);
   visitor->Trace(focus_node_);

third_party/blink/renderer/core/testing/static_selection.h

@@ -17,14 +17,17 @@ class StaticSelection final : public ScriptWrappable {
   DEFINE_WRAPPERTYPEINFO();
 
  public:
+  static StaticSelection* FromSelectionInDOMTree(const SelectionInDOMTree&);
   static StaticSelection* FromSelectionInFlatTree(const SelectionInFlatTree&);
 
   explicit StaticSelection(const SelectionInFlatTree&);
+  explicit StaticSelection(const SelectionInDOMTree&);
 
   Node* anchorNode() const { return anchor_node_; }
   unsigned anchorOffset() const { return anchor_offset_; }
   Node* focusNode() const { return focus_node_; }
   unsigned focusOffset() const { return focus_offset_; }
+  bool isCollapsed() const;
 
   void Trace(blink::Visitor*) override;
 

third_party/blink/renderer/core/testing/static_selection.idl

@@ -7,4 +7,5 @@ interface StaticSelection {
     readonly attribute unsigned long anchorOffset;
     readonly attribute Node? focusNode;
     readonly attribute unsigned long focusOffset;
+    readonly attribute boolean isCollapsed;
 };

third_party/blink/web_tests/TestExpectations

@@ -1741,7 +1741,6 @@ crbug.com/891427 virtual/android/url-bar/bottom-and-top-fixed-sticks-to-top.html
 ## Next 4 here: https://ci.chromium.org/p/chromium/builders/luci.chromium.try/linux_chromium_rel_ng/216317
 crbug.com/891427 virtual/threaded/animations/timing/animation-duration-infinite.html [ Failure ]
 crbug.com/891427 virtual/disable-blink-gen-property-trees/animations/timing/animation-duration-infinite.html [ Skip ]
-crbug.com/891427 editing/selection/drag-in-iframe.html [ Failure ]
 crbug.com/891427 fast/overflow/transformed-frame-scrollIntoView.html [ Crash ]
 
 ### Flaky on trybots:

third_party/blink/web_tests/editing/selection/drag-in-iframe.html

@@ -1,14 +1,16 @@
-<html>
-<body contenteditable="true" onload="test()">
+<!doctype html>
+<script src="../../resources/testharness.js"></script>
+<script src="../../resources/testharnessreport.js"></script>
+<body contenteditable="true">
     <p>
-        This is an automatic pixel test. To test interactively, drag selected text onto the iframe
+        To test interactively, drag selected text onto the iframe
         below and verify that a drag caret appears inside the frame.
     </p>
     <iframe id="subframe" style="border: 1px solid black;"
         srcdoc="<body contenteditable><span id='target'>There</span> should be a caret here --> <br>See it?</body>"></iframe>
     <script>
-        function dragAndDrop()
-        {
+        const t = async_test('Drag-In-Iframge');
+        window.addEventListener('load', t.step_func_done(() => {
             var iframe = document.getElementById("subframe");
             var target = iframe.contentDocument.getElementById("target");
 
@@ -18,27 +20,29 @@
 
             iframe.contentWindow.getSelection().setBaseAndExtent(target, 0, target, 1);
 
+            assert_own_property(window, 'eventSender');
+            assert_own_property(window, 'internals');
+
             eventSender.mouseMoveTo(x1, y);
             eventSender.dragMode = false;
             eventSender.mouseDown();
             eventSender.leapForward(1000);
             eventSender.mouseMoveTo(x2, y);
-
-            // Dump pixel results before we drop so we can see where the drag caret is painted.
-            testRunner.notifyDone();
 
-            // Pixel dumping is asynchronous. We still have chance to send mouseUp.
-            setTimeout(function() { eventSender.mouseUp(); }, 0);
-        }
-
-        function test()
-        {
-            if (!window.testRunner)
-                return;
+            const caretInMainFrame = internals.getDragCaret();
+            assert_equals(caretInMainFrame.anchorNode, null,
+                          'No drag caret in main frame');
+
+            const caretInIframe = iframe.contentWindow.internals.getDragCaret();
+            assert_true(caretInIframe.isCollapsed,
+                          'Caret in iframe should be collapsed');
+            const textBeforeCaret= target.nextSibling;
+            assert_equals(caretInIframe.anchorNode, textBeforeCaret);
+            assert_equals(caretInIframe.anchorOffset, textBeforeCaret.length);
 
-            testRunner.waitUntilDone();
-            setTimeout(dragAndDrop, 0);
-        }
+            // To avoid crash, we should release mouse button.
+            eventSender.mouseUp();
+        }));
     </script>
 </body>
 </html>