Bug 1197765 - Compare text content inside frame instead of the content node for ruby autohiding. r=dbaron

dom/base/nsContentUtils.h

@@ -1312,6 +1312,8 @@ public:
    * are not converted into newlines. Only textnodes and cdata nodes are
    * added to the result.
    *
+   * @see nsLayoutUtils::GetFrameTextContent
+   *
    * @param aNode Node to get textual contents of.
    * @param aDeep If true child elements of aNode are recursivly descended
    *              into to find text children.

layout/base/nsLayoutUtils.cpp

@@ -8577,3 +8577,26 @@ nsLayoutUtils::ShouldUseNoFramesSheet(nsIDocument* aDocument)
   }
   return !allowSubframes;
 }
+
+/* static */ void
+nsLayoutUtils::GetFrameTextContent(nsIFrame* aFrame, nsAString& aResult)
+{
+  aResult.Truncate();
+  AppendFrameTextContent(aFrame, aResult);
+}
+
+/* static */ void
+nsLayoutUtils::AppendFrameTextContent(nsIFrame* aFrame, nsAString& aResult)
+{
+  if (aFrame->GetType() == nsGkAtoms::textFrame) {
+    auto textFrame = static_cast<nsTextFrame*>(aFrame);
+    auto offset = textFrame->GetContentOffset();
+    auto length = textFrame->GetContentLength();
+    textFrame->GetContent()->
+      GetText()->AppendTo(aResult, offset, length);
+  } else {
+    for (nsIFrame* child : aFrame->PrincipalChildList()) {
+      AppendFrameTextContent(child, aResult);
+    }
+  }
+}

layout/base/nsLayoutUtils.h

@@ -2719,6 +2719,26 @@ public:
   static bool ShouldUseNoScriptSheet(nsIDocument* aDocument);
   static bool ShouldUseNoFramesSheet(nsIDocument* aDocument);
 
+  /**
+   * Get the text content inside the frame. This methods traverse the
+   * frame tree and collect the content from text frames. Note that this
+   * method is similiar to nsContentUtils::GetNodeTextContent, but it at
+   * least differs from that method in the following things:
+   * 1. it skips text content inside nodes like style, script, textarea
+   *    which don't generate an in-tree text frame for the text;
+   * 2. it skips elements with display property set to none;
+   * 3. it skips out-of-flow elements;
+   * 4. it includes content inside pseudo elements;
+   * 5. it may include part of text content of a node if a text frame
+   *    inside is split to different continuations.
+   */
+  static void GetFrameTextContent(nsIFrame* aFrame, nsAString& aResult);
+
+  /**
+   * Same as GetFrameTextContent but appends the result rather than sets it.
+   */
+  static void AppendFrameTextContent(nsIFrame* aFrame, nsAString& aResult);
+
 private:
   static uint32_t sFontSizeInflationEmPerLine;
   static uint32_t sFontSizeInflationMinTwips;

layout/generic/nsRubyBaseContainerFrame.cpp

@@ -13,7 +13,7 @@
 #include "mozilla/DebugOnly.h"
 #include "mozilla/Maybe.h"
 #include "mozilla/WritingModes.h"
-#include "nsContentUtils.h"
+#include "nsLayoutUtils.h"
 #include "nsLineLayout.h"
 #include "nsPresContext.h"
 #include "nsStyleContext.h"
@@ -609,8 +609,7 @@ nsRubyBaseContainerFrame::ReflowOneColumn(const ReflowState& aReflowState,
 
   nsAutoString baseText;
   if (aColumn.mBaseFrame) {
-    nsContentUtils::GetNodeTextContent(aColumn.mBaseFrame->GetContent(),
-                                       true, baseText);
+    nsLayoutUtils::GetFrameTextContent(aColumn.mBaseFrame, baseText);
   }
 
   // Reflow text frames
@@ -618,8 +617,7 @@ nsRubyBaseContainerFrame::ReflowOneColumn(const ReflowState& aReflowState,
     nsRubyTextFrame* textFrame = aColumn.mTextFrames[i];
     if (textFrame) {
       nsAutoString annotationText;
-      nsContentUtils::GetNodeTextContent(textFrame->GetContent(),
-                                         true, annotationText);
+      nsLayoutUtils::GetFrameTextContent(textFrame, annotationText);
 
       // Per CSS Ruby spec, the content comparison for auto-hiding
       // takes place prior to white spaces collapsing (white-space)

layout/reftests/w3c-css/submitted/ruby/reftest.list

@@ -9,4 +9,5 @@
 == ruby-autohide-001.html ruby-autohide-001-ref.html
 == ruby-autohide-002.html ruby-autohide-002-ref.html
 == ruby-autohide-003.html ruby-autohide-003-ref.html
+== ruby-autohide-004.html ruby-autohide-001-ref.html
 

layout/reftests/w3c-css/submitted/ruby/ruby-autohide-004.html

@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<html lang="ja">
+<head>
+  <meta charset="UTF-8">
+  <title>CSS Test: Autohide ruby annotations which are identical to their bases</title>
+  <link rel="author" title="Xidorn Quan" href="mailto:quanxunzhen@gmail.com">
+  <link rel="help" href="http://www.w3.org/TR/css-ruby-1/#autohide">
+  <link rel="match" href="ruby-autohide-001-ref.html">
+</head>
+<body>
+  <ruby>
+    振<rt>ふ</rt>り<rt>り</rt>仮<rt>が</rt>名<rt>な</rt>
+  </ruby>
+</body>
+</html>