On Android, unlabeled link containing image should use image url as name.

This is just a heuristic to handle a situation where neither the link or
image are labeled. Since we can only export a single name attribute on
Android - unlike other systems where we export several fields and let the
assistive technology decide - this tries to do the sensible thing when
there's a link containing an image.

BUG=386623

Review URL: https://codereview.chromium.org/639773012

Cr-Commit-Position: refs/heads/master@{#301390}

content/browser/accessibility/browser_accessibility_android.cc

@@ -327,14 +327,16 @@ base::string16 BrowserAccessibilityAndroid::GetText() const {
 
   // This is called from PlatformIsLeaf, so don't call PlatformChildCount
   // from within this!
-  if (text.empty() && HasOnlyStaticTextChildren()) {
+  if (text.empty() &&
+      (HasOnlyStaticTextChildren() ||
+       (IsFocusable() && HasOnlyTextAndImageChildren()))) {
     for (uint32 i = 0; i < InternalChildCount(); i++) {
       BrowserAccessibility* child = InternalGetChild(i);
       text += static_cast<BrowserAccessibilityAndroid*>(child)->GetText();
     }
   }
 
-  if (text.empty() && IsLink()) {
+  if (text.empty() && (IsLink() || GetRole() == ui::AX_ROLE_IMAGE)) {
     base::string16 url = GetString16Attribute(ui::AX_ATTR_URL);
     // Given a url like http://foo.com/bar/baz.png, just return the
     // base name, e.g., "baz".
@@ -621,6 +623,19 @@ bool BrowserAccessibilityAndroid::HasOnlyStaticTextChildren() const {
   return true;
 }
 
+bool BrowserAccessibilityAndroid::HasOnlyTextAndImageChildren() const {
+  // This is called from PlatformIsLeaf, so don't call PlatformChildCount
+  // from within this!
+  for (uint32 i = 0; i < InternalChildCount(); i++) {
+    BrowserAccessibility* child = InternalGetChild(i);
+    if (child->GetRole() != ui::AX_ROLE_STATIC_TEXT &&
+        child->GetRole() != ui::AX_ROLE_IMAGE) {
+      return false;
+    }
+  }
+  return true;
+}
+
 bool BrowserAccessibilityAndroid::IsIframe() const {
   base::string16 html_tag = GetString16Attribute(
       ui::AX_ATTR_HTML_TAG);

content/browser/accessibility/browser_accessibility_android.h

@@ -86,6 +86,7 @@ class BrowserAccessibilityAndroid : public BrowserAccessibility {
   BrowserAccessibilityAndroid();
 
   bool HasOnlyStaticTextChildren() const;
+  bool HasOnlyTextAndImageChildren() const;
   bool IsIframe() const;
 
   void NotifyLiveRegionUpdate(base::string16& aria_live);

content/test/data/accessibility/a-no-text-expected-android.txt

@@ -8,3 +8,5 @@ android.webkit.WebView focusable focused scrollable
         android.view.View clickable focusable name='dest6'
         android.view.View clickable focusable name='dest7'
         android.view.View clickable focusable name='dest.8'
+        android.view.View clickable focusable name='greenbox'
+        android.view.View clickable focusable name='greenbox'

content/test/data/accessibility/a-no-text.html

@@ -11,5 +11,7 @@
   <a href="dest6.html"><img src="#"> </a>
   <a href="http://example.com/dest7.html"><img src="#"> </a>
   <a href="http://example.com/dest.8.html"><img src="#"> </a>
+  <a href="dest9.html"><img src="greenbox.png"></a>
+  <a href="dest10.html"><img src="greenbox.png"> </a>
 </body>
 </html>