Fix accessibility objects with zero width and height.

content/browser/accessibility/browser_accessibility.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/accessibility/browser_accessibility.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 170 matching lines @@
   return GetData().state;
 }
 
 const BrowserAccessibility::HtmlAttributes&
 BrowserAccessibility::GetHtmlAttributes() const {
   return GetData().html_attributes;
 }
 
 gfx::Rect BrowserAccessibility::GetLocalBoundsRect() const {
   gfx::Rect bounds = GetLocation();
+  FixEmptyBounds(&bounds);
   return ElementBoundsToLocalBounds(bounds);
 }
 
 gfx::Rect BrowserAccessibility::GetGlobalBoundsRect() const {
   gfx::Rect bounds = GetLocalBoundsRect();
 
   // Adjust the bounds by the top left corner of the containing view's bounds
   // in screen coordinates.
   bounds.Offset(manager_->GetViewBounds().OffsetFromOrigin());
 
@@ skipping 487 matching lines @@
   ui::AXNode* parent = node_->parent();
   if (parent)
     return manager_->GetFromAXNode(parent);
 
   if (!manager_->delegate())
     return NULL;
 
   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
   // based on the scroll bars and then offset based on the origin of that
   // nested web area.
   BrowserAccessibility* parent = GetParentForBoundsCalculation();
   bool need_to_offset_web_area =
       (GetRole() == ui::AX_ROLE_WEB_AREA ||
        GetRole() == ui::AX_ROLE_ROOT_WEB_AREA);
   while (parent) {
@@ skipping 21 matching lines @@
       }
       need_to_offset_web_area = true;
     }
     parent = parent->GetParentForBoundsCalculation();
   }
 
   return bounds;
 }
 
 }  // namespace content