Disallow tabsToLinks setting to prevent tabbing to anchor with tabIndex.

Source/core/html/HTMLAnchorElement.cpp

Index: Source/core/html/HTMLAnchorElement.cpp
diff --git a/Source/core/html/HTMLAnchorElement.cpp b/Source/core/html/HTMLAnchorElement.cpp
index ad2524376d2764a9725c70eb8a93436c08ffed24..f9b7a11f8cd07cc0dd859105c3131e42de754f6d 100644
--- a/Source/core/html/HTMLAnchorElement.cpp
+++ b/Source/core/html/HTMLAnchorElement.cpp
@@ -137,12 +137,13 @@ bool HTMLAnchorElement::isMouseFocusable() const
 
 bool HTMLAnchorElement::isKeyboardFocusable(KeyboardEvent* event) const
 {
-    if (!isLink())
-        return HTMLElement::isKeyboardFocusable(event);
-
     if (!isFocusable())
         return false;
-    
+
+    // If tab index set explicitly, decide focus regardless of the tabsToLinks setting.

[dmazzoni, 2013/08/01 21:48:15]

Well, technically you're also skipping the test that document()->page() exists,
and the canvas subtree and hasNonEmptyBoundingBox tests.

I think bypassing the canvas subtree and hasNonEmptyBoundingBox tests  make
sense, but you should mention that in the comment, something more like:

// If the tab index is set explicitly, ignore the tabsToLinks
// setting and empty bounding box check.

Is there ever a case when the page doesn't exist, or is that just
a defensive test?

[rchl, 2013/08/20 17:58:10]

I can't say for sure but the first "!isLink()" condition that I've removed could
also return true without checking if page existed so I guess it was fine. It
seems like the 'page' variable is used solely for the tabsToLinks check and
probably the code is just being defensive.

+    if (Element::supportsFocus())
+        return HTMLElement::isKeyboardFocusable(event);
+
     Page* page = document()->page();
     if (!page)
         return false;