Fix accessibility objects with zero width and height.

content/browser/accessibility/browser_accessibility.cc

Index: content/browser/accessibility/browser_accessibility.cc
diff --git a/content/browser/accessibility/browser_accessibility.cc b/content/browser/accessibility/browser_accessibility.cc
index b50a47662f01504097641479285641aa058f995c..c71cee6800c01d3a195114d854082d59b2ff8114 100644
--- a/content/browser/accessibility/browser_accessibility.cc
+++ b/content/browser/accessibility/browser_accessibility.cc
@@ -188,6 +188,7 @@ BrowserAccessibility::GetHtmlAttributes() const {
 
 gfx::Rect BrowserAccessibility::GetLocalBoundsRect() const {
   gfx::Rect bounds = GetLocation();
+  FixEmptyBounds(&bounds);
   return ElementBoundsToLocalBounds(bounds);
 }
 
@@ -695,6 +696,21 @@ BrowserAccessibility* BrowserAccessibility::GetParentForBoundsCalculation()
   return manager_->delegate()->AccessibilityGetParentFrame();
 }
 
+void BrowserAccessibility::FixEmptyBounds(gfx::Rect* bounds) const
+{
+  if (bounds->width() > 0 && bounds->height() > 0)
+    return;
+
+  for (size_t i = 0; i < InternalChildCount(); ++i) {
+    BrowserAccessibility* child = InternalGetChild(i);
+    gfx::Rect child_bounds = child->GetLocalBoundsRect();
+    if (bounds->width() > 0 && bounds->height() > 0)
+      bounds->Union(child_bounds);
+    else

[David Tseng, 2015/06/22 21:29:36]

I'm confused why you have this branch at all?

[dmazzoni, 2015/06/23 05:36:42]

If the width and height are already nonzero the function early-exits at the top.

Otherwise we enter the loop. The first time through the loop it will set *bounds
to the bounds of the first child, after that it will union it.

[David Tseng, 2015/06/23 18:27:53]

So, you're assuming child's height and width are never both 0? Is this always
the case? Could you make this more explicit by checking the index in this
branch?

[dmazzoni, 2015/06/23 23:37:11]

OK, I made this more explicit and added a comment.

However, this made me realize that we shouldn't assume the child bounds are
nonempty. Fixed that too.

+      *bounds = child_bounds;
+  }
+}
+
 gfx::Rect BrowserAccessibility::ElementBoundsToLocalBounds(gfx::Rect bounds)
     const {
   // Walk up the parent chain. Every time we encounter a Web Area, offset