Spaces getting eaten between words in rare cases

When two spans are separated by a line break, and the second span's text node
also begins with a line break, the space shown in the layout is not rendered
in the accessibility presentation.

The computation to determine if there is rendered space adjacent to a space-only
node must use the inline text boxes to get the most accurate representation
of what is ultimately rendered.

Bug: 821906
Change-Id: Ie81134a95a8878d22a370e97b330e0eae5101d67
Reviewed-on: https://chromium-review.googlesource.com/988375
Commit-Queue: Aaron Leventhal <aleventhal@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#547589}

content/test/data/accessibility/html/span-expected-blink.txt

@@ -86,4 +86,33 @@ rootWebArea
 ++++staticText name=' '
 ++++++inlineTextBox name=' '
 ++++staticText name='space'
-++++++inlineTextBox name='space'
+++++++inlineTextBox name='space'
\ No newline at end of file
+++paragraph
+++++staticText name='K4. Keep '
+++++++inlineTextBox name='K4. Keep '
+++++staticText name='space'
+++++++inlineTextBox name='space'
+++paragraph
+++++staticText name='K5. Keep'
+++++++inlineTextBox name='K5. Keep'
+++++staticText name=' '
+++++++inlineTextBox name=' '
+++++staticText name='space'
+++++++inlineTextBox name='space'
+++paragraph
+++++staticText name='K6. Keep '
+++++++inlineTextBox name='K6. Keep '
+++++staticText name='space'
+++++++inlineTextBox name='space'
+++paragraph
+++++staticText name='K7. Keep'
+++++++inlineTextBox name='K7. Keep'
+++++staticText name=' space'
+++++++inlineTextBox name=' space'
+++paragraph
+++++staticText name='K8. Keep'
+++++++inlineTextBox name='K8. Keep'
+++++staticText name=' '
+++++++inlineTextBox name=' '
+++++staticText name='space'
+++++++inlineTextBox name='space'

content/test/data/accessibility/html/span-expected-mac.txt

@@ -50,4 +50,21 @@ AXWebArea
 ++AXGroup
 ++++AXStaticText AXValue='K3. Keep'
 ++++AXStaticText AXValue=' '
-++++AXStaticText AXValue='space'
+++++AXStaticText AXValue='space'
\ No newline at end of file
+++AXGroup
+++++AXStaticText AXValue='K4. Keep '
+++++AXStaticText AXValue='space'
+++AXGroup
+++++AXStaticText AXValue='K5. Keep'
+++++AXStaticText AXValue=' '
+++++AXStaticText AXValue='space'
+++AXGroup
+++++AXStaticText AXValue='K6. Keep '
+++++AXStaticText AXValue='space'
+++AXGroup
+++++AXStaticText AXValue='K7. Keep'
+++++AXStaticText AXValue=' space'
+++AXGroup
+++++AXStaticText AXValue='K8. Keep'
+++++AXStaticText AXValue=' '
+++++AXStaticText AXValue='space'

content/test/data/accessibility/html/span-expected-win.txt

@@ -50,4 +50,21 @@ ROLE_SYSTEM_DOCUMENT READONLY FOCUSABLE
 ++IA2_ROLE_PARAGRAPH
 ++++ROLE_SYSTEM_STATICTEXT name='K3. Keep'
 ++++ROLE_SYSTEM_STATICTEXT name=' '
-++++ROLE_SYSTEM_STATICTEXT name='space'
+++++ROLE_SYSTEM_STATICTEXT name='space'
\ No newline at end of file
+++IA2_ROLE_PARAGRAPH
+++++ROLE_SYSTEM_STATICTEXT name='K4. Keep '
+++++ROLE_SYSTEM_STATICTEXT name='space'
+++IA2_ROLE_PARAGRAPH
+++++ROLE_SYSTEM_STATICTEXT name='K5. Keep'
+++++ROLE_SYSTEM_STATICTEXT name=' '
+++++ROLE_SYSTEM_STATICTEXT name='space'
+++IA2_ROLE_PARAGRAPH
+++++ROLE_SYSTEM_STATICTEXT name='K6. Keep '
+++++ROLE_SYSTEM_STATICTEXT name='space'
+++IA2_ROLE_PARAGRAPH
+++++ROLE_SYSTEM_STATICTEXT name='K7. Keep'
+++++ROLE_SYSTEM_STATICTEXT name=' space'
+++IA2_ROLE_PARAGRAPH
+++++ROLE_SYSTEM_STATICTEXT name='K8. Keep'
+++++ROLE_SYSTEM_STATICTEXT name=' '
+++++ROLE_SYSTEM_STATICTEXT name='space'

content/test/data/accessibility/html/span.html

@@ -36,5 +36,26 @@
   <p>
     <span>K3. Keep</span><i><b> </b></i><span>space</span>
   </p>
-</body>
-</html>
+
+<!-- Blank line between spans and at end of first text node -->
+<p><span>K4. Keep
+</span>
+<span>space</span></p>
+
+<!-- Blank line between spans and at start of second text node-->
+<p><span>K5. Keep</span>
+<span>
+space</span></p>
+
+<!-- Blank line at end of first text node -->
+<p><span>K6. Keep
+</span><span>space</span></p>
+
+<!-- Blank line at start of second text node -->
+<p><span>K7. Keep</span><span>
+space</span></p>
+
+<!-- Blank line between spans -->
+<p><span>K8. Keep</span>
+<span>space</span></p>
+</body></html>

third_party/WebKit/Source/modules/accessibility/AXLayoutObject.cpp

@@ -774,9 +774,14 @@ bool AXLayoutObject::CanIgnoreSpaceNextTo(LayoutObject* layout,
     LayoutText* layout_text = ToLayoutText(layout);
     if (layout_text->HasEmptyText())
       return false;
-    auto text = layout_text->GetText().Impl();
+    if (layout_text->GetText().Impl()->ContainsOnlyWhitespace())
+      return true;
+    DCHECK(layout_text->HasTextBoxes());
+    InlineTextBox* adjacent =
+        is_after ? layout_text->FirstTextBox() : layout_text->LastTextBox();
+    auto text = adjacent->GetText();
     auto adjacent_char =
-        text->CharacterStartingAt(is_after ? 0 : text->length() - 1);
+        text.CharacterStartingAt(is_after ? 0 : text.length() - 1);
     return adjacent_char == ' ' || adjacent_char == '\n' ||
            adjacent_char == '\t';
   }