Bug 1940377 - part 4: Make HTMLEditor normalize white-spaces before inserting HTML fragment if the new normalizer is enabled r=m_kato

Unfortunately, this change does not make
`white-spaces-after-insert-image.tentative.html?paste-image` pass because we
paste the `<div>` at pasting the `<img>`, but Chrome pastes only the `<img>`.

Differential Revision: https://phabricator.services.mozilla.com/D239466

editor/libeditor/HTMLEditSubActionHandler.cpp

@@ -561,11 +561,10 @@ nsresult HTMLEditor::OnEndHandlingTopLevelEditSubActionInternal() {
         case EditSubAction::eInsertTextComingFromIME:
         case EditSubAction::eInsertLineBreak:
         case EditSubAction::eInsertParagraphSeparator:
-          return !StaticPrefs::
-              editor_white_space_normalization_blink_compatible();
         case EditSubAction::ePasteHTMLContent:
         case EditSubAction::eInsertHTMLSource:
-          return true;
+          return !StaticPrefs::
+              editor_white_space_normalization_blink_compatible();
         default:
           return false;
       }

editor/libeditor/HTMLEditorDataTransfer.cpp

@@ -46,6 +46,7 @@
 #include "mozilla/OwningNonNull.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/Result.h"
+#include "mozilla/StaticPrefs_editor.h"
 #include "mozilla/TextComposition.h"
 #include "nsAString.h"
 #include "nsCOMPtr.h"
@@ -847,6 +848,22 @@ Result<EditActionResult, nsresult> HTMLEditor::HTMLWithContextInserter::Run(
     NS_WARNING("HTMLEditor::GetBetterInsertionPointFor() failed");
     return Err(NS_ERROR_FAILURE);
   }
+  if (StaticPrefs::editor_white_space_normalization_blink_compatible()) {
+    Result<EditorDOMPoint, nsresult> pointToInsertOrError =
+        WhiteSpaceVisibilityKeeper::NormalizeWhiteSpacesToSplitAt(
+            mHTMLEditor, pointToInsert,
+            {WhiteSpaceVisibilityKeeper::NormalizeOption::
+                 StopIfFollowingWhiteSpacesStartsWithNBSP});
+    if (MOZ_UNLIKELY(pointToInsertOrError.isErr())) {
+      NS_WARNING(
+          "WhiteSpaceVisibilityKeeper::NormalizeWhiteSpacesToSplitAt() failed");
+      return pointToInsertOrError.propagateErr();
+    }
+    pointToInsert = pointToInsertOrError.unwrap();
+    if (NS_WARN_IF(!pointToInsert.IsSetAndValidInComposedDoc())) {
+      return Err(NS_ERROR_EDITOR_UNEXPECTED_DOM_TREE);
+    }
+  }
 
   const bool insertionPointWasInLink =
       !!HTMLEditor::GetLinkElement(pointToInsert.GetContainer());

testing/web-platform/meta/editing/whitespaces/chrome-compat/insert-or-paste-image.tentative.html.ini

@@ -60,32 +60,3 @@
 
 
 [insert-or-paste-image.tentative.html?execCommand-insertHTML]
-  [document.execCommand("insertHTML") when "a[\]         b"]
-    expected: FAIL
-
-  [document.execCommand("insertHTML") when "a [\]        b"]
-    expected: FAIL
-
-  [document.execCommand("insertHTML") when "a  [\]       b"]
-    expected: FAIL
-
-  [document.execCommand("insertHTML") when "a   [\]      b"]
-    expected: FAIL
-
-  [document.execCommand("insertHTML") when "a    [\]     b"]
-    expected: FAIL
-
-  [document.execCommand("insertHTML") when "a     [\]    b"]
-    expected: FAIL
-
-  [document.execCommand("insertHTML") when "a      [\]   b"]
-    expected: FAIL
-
-  [document.execCommand("insertHTML") when "a       [\]  b"]
-    expected: FAIL
-
-  [document.execCommand("insertHTML") when "a        [\] b"]
-    expected: FAIL
-
-  [document.execCommand("insertHTML") when "a         [\]b"]
-    expected: FAIL