Ignore images with an explicitly empty alt attribute.

Images with an explicitly empty alt attribute should be ignored.
Images that do not have the alt attribute explicitly empty will have
automatic image annotation done when possible, so we shouldn't ignore
them.

Bug: 1018853
Change-Id: If8f95d8ed7376797e24707047b5b291bde1555bc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1881124
Commit-Queue: Jacques Newman <janewman@microsoft.com>
Reviewed-by: Alice Boxhall <aboxhall@chromium.org>
Reviewed-by: Kurt Catti-Schmidt <kschmi@microsoft.com>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#713564}

content/test/data/accessibility/html/img-empty-alt-expected-android.txt

 android.webkit.WebView focusable focused scrollable
 ++android.view.View
-++++android.widget.Image role_description='graphic'
-++++android.widget.Image role_description='graphic'
 ++++android.widget.Image role_description='graphic' name='read'
 ++++android.widget.Image role_description='graphic' name='full'

content/test/data/accessibility/html/img-empty-alt-expected-auralinux.txt

 [document web]
 ++[section]
-++++[image] name=''
-++++[image] name=''
 ++++[image]
 ++++[image] name='full'

content/test/data/accessibility/html/img-empty-alt-expected-blink.txt

 rootWebArea
 ++genericContainer
 ++++presentational ignored name=''
-++++image name=''
-++++image name=''
+++++image ignored name=''
+++++image ignored name=''
 ++++image
 ++++image name='full'

content/test/data/accessibility/html/img-empty-alt-expected-mac.txt

 AXWebArea
 ++AXGroup
-++++AXUnknown
-++++AXUnknown
 ++++AXImage AXDescription='/read.jpg'
 ++++AXImage AXDescription='full'

content/test/data/accessibility/html/img-empty-alt-expected-uia-win.txt

 document
 ++group
 ++++img
-++++img
-++++img
 ++++img Name='full'

content/test/data/accessibility/html/img-empty-alt-expected-win.txt

 ROLE_SYSTEM_DOCUMENT READONLY FOCUSABLE
 ++IA2_ROLE_SECTION
-++++ROLE_SYSTEM_GRAPHIC name='' READONLY
-++++ROLE_SYSTEM_GRAPHIC name='' READONLY
 ++++ROLE_SYSTEM_GRAPHIC READONLY
 ++++ROLE_SYSTEM_GRAPHIC name='full' READONLY

content/test/data/accessibility/html/img-expected-android.txt

@@ -2,6 +2,5 @@ android.webkit.WebView focusable focused has_image scrollable
 ++android.view.View has_image
 ++++android.widget.Image role_description='graphic' has_image name='pipe'
 ++++android.view.View name=' '
-++++android.widget.Image role_description='graphic' has_image
 ++++android.view.View name=' '
 ++++android.widget.Image role_description='graphic' has_image name='  '

content/test/data/accessibility/html/img-expected-auralinux.txt

@@ -2,6 +2,5 @@
 ++[section]
 ++++[image] name='pipe' xml-roles:img
 ++++[static] name=' '
-++++[image] name='' xml-roles:img
 ++++[static] name=' '
-++++[image] name='  ' xml-roles:img
+++++[image] name='  ' xml-roles:img
\ No newline at end of file

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

@@ -3,7 +3,6 @@ rootWebArea
 ++++image name='pipe'
 ++++staticText name=' '
 ++++++inlineTextBox name=' '
-++++image name=''
 ++++staticText name=' '
 ++++++inlineTextBox name=' '
 ++++image name='  '

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

@@ -2,6 +2,5 @@ AXWebArea
 ++AXGroup
 ++++AXImage AXRoleDescription='image' AXDescription='pipe'
 ++++AXStaticText AXValue=' '
-++++AXUnknown
 ++++AXStaticText AXValue=' '
 ++++AXImage AXRoleDescription='image' AXDescription='  '
\ No newline at end of file

content/test/data/accessibility/html/img-expected-uia-win.txt

@@ -2,6 +2,5 @@ document
 ++group
 ++++img Name='pipe'
 ++++description Name=' '
-++++img
 ++++description Name=' '
 ++++img Name='  '

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

@@ -2,6 +2,5 @@ ROLE_SYSTEM_DOCUMENT READONLY FOCUSABLE
 ++IA2_ROLE_SECTION
 ++++ROLE_SYSTEM_GRAPHIC name='pipe' READONLY xml-roles:img
 ++++ROLE_SYSTEM_STATICTEXT name=' '
-++++ROLE_SYSTEM_GRAPHIC name='' READONLY xml-roles:img
 ++++ROLE_SYSTEM_STATICTEXT name=' '
 ++++ROLE_SYSTEM_GRAPHIC name='  ' READONLY xml-roles:img

content/test/data/accessibility/html/img-link-empty-alt-expected-auralinux.txt

@@ -3,11 +3,9 @@
 ++++[link] name='unread '
 ++++++[static] name='unread '
 ++++[link] name='read '
-++++++[image] name=''
 ++++++[static] name='read '
 ++++[link] name='read '
-++++++[image] name=''
 ++++++[static] name='read '
 ++++[link] name='read'
 ++++++[image]
-++++++[static] name='read'
+++++++[static] name='read'
\ No newline at end of file

content/test/data/accessibility/html/img-link-empty-alt-expected-blink.txt

@@ -5,11 +5,11 @@ rootWebArea
 ++++++staticText name='unread '
 ++++++++inlineTextBox name='unread '
 ++++link name='read '
-++++++image name=''
+++++++image ignored name=''
 ++++++staticText name='read '
 ++++++++inlineTextBox name='read '
 ++++link name='read '
-++++++image name=''
+++++++image ignored name=''
 ++++++staticText name='read '
 ++++++++inlineTextBox name='read '
 ++++link name='read'

content/test/data/accessibility/html/img-link-empty-alt-expected-mac.txt

@@ -3,10 +3,8 @@ AXWebArea
 ++++AXLink AXTitle='unread '
 ++++++AXStaticText AXValue='unread '
 ++++AXLink AXTitle='read '
-++++++AXUnknown
 ++++++AXStaticText AXValue='read '
 ++++AXLink AXTitle='read '
-++++++AXUnknown
 ++++++AXStaticText AXValue='read '
 ++++AXLink AXTitle='read'
 ++++++AXImage AXDescription='/read.jpg'

content/test/data/accessibility/html/img-link-empty-alt-expected-uia-win.txt

@@ -2,8 +2,6 @@ document
 ++group
 ++++link Name='unread '
 ++++link Name='read '
-++++++img
 ++++link Name='read '
-++++++img
 ++++link Name='read'
 ++++++img

content/test/data/accessibility/html/img-link-empty-alt-expected-win.txt

@@ -3,10 +3,8 @@ ROLE_SYSTEM_DOCUMENT READONLY FOCUSABLE
 ++++ROLE_SYSTEM_LINK name='unread ' FOCUSABLE
 ++++++ROLE_SYSTEM_STATICTEXT name='unread '
 ++++ROLE_SYSTEM_LINK name='read ' FOCUSABLE
-++++++ROLE_SYSTEM_GRAPHIC name='' READONLY
 ++++++ROLE_SYSTEM_STATICTEXT name='read '
 ++++ROLE_SYSTEM_LINK name='read ' FOCUSABLE
-++++++ROLE_SYSTEM_GRAPHIC name='' READONLY
 ++++++ROLE_SYSTEM_STATICTEXT name='read '
 ++++ROLE_SYSTEM_LINK name='read' FOCUSABLE
 ++++++ROLE_SYSTEM_GRAPHIC READONLY

third_party/blink/renderer/modules/accessibility/ax_node_object.cc

@@ -287,9 +287,14 @@ AXObjectInclusion AXNodeObject::ShouldIncludeBasedOnSemantics(
   if (HasGlobalARIAAttribute())
     return kIncludeObject;
 
-  if (IsImage())
-    return kIncludeObject;
-
+  bool has_non_empty_alt_attribute = !GetAttribute(kAltAttr).IsEmpty();
+  if (IsImage()) {
+    if (has_non_empty_alt_attribute || GetAttribute(kAltAttr).IsNull())
+      return kIncludeObject;
+    else if (ignored_reasons)
+      ignored_reasons->push_back(IgnoredReason(kAXEmptyAlt));
+    return kIgnoreObject;
+  }
   // Using the title or accessibility description (so we
   // check if there's some kind of accessible name for the element)
   // to decide an element's visibility is not as definitive as
@@ -298,8 +303,8 @@ AXObjectInclusion AXNodeObject::ShouldIncludeBasedOnSemantics(
   // These checks are simplified in the interest of execution speed;
   // for example, any element having an alt attribute will make it
   // not ignored, rather than just images.
-  if (HasAriaAttribute(GetElement()) || !GetAttribute(kAltAttr).IsEmpty() ||
-      !GetAttribute(kTitleAttr).IsEmpty())
+  if (HasAriaAttribute(GetElement()) || !GetAttribute(kTitleAttr).IsEmpty() ||
+      has_non_empty_alt_attribute)
     return kIncludeObject;
 
   // <span> tags are inline tags and not meant to convey information if they