Revert of Do the early return when role is different than UnknownRole…

… (patchset #1 id:1 of https://codereview.chromium.org/756823004/)

Reason for revert:
Two Nexus 4 tests started crashing after this change:

ast/animation/request-animation-frame-callback-id.html
svg/canvas/canvas-pattern-svg.html

See eg

http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=fast%2Fanimation%2Frequest-animation-frame-callback-id.html&testType=layout-tests

First failure is here:

http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Android%20%28Nexus4%29/builds/23692

However the Nexus 4 bot is exhibiting other problems from build 23691 that might be related. So this is a speculative rollout.

Original issue's description:
> Do the early return when role is different than UnknownRole
> 
> We do not need to call ariaRoleAttribute() to check whether current role
> is different than UnknownRole. Just check m_ariaRole instead.
> 
> BUG=
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=186527

TBR=dmazzoni@chromium.org,k.czech@samsung.com
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/773213003

git-svn-id: svn://svn.chromium.org/blink/trunk@186566 bbb929c8-8fbe-4397-9dbb-9b2b20218538

Source/modules/accessibility/AXTableRow.cpp

@@ -56,8 +56,11 @@ AccessibilityRole AXTableRow::determineAccessibilityRole()
     if (!isTableRow())
         return AXRenderObject::determineAccessibilityRole();
 
-    if ((m_ariaRole = determineAriaRoleAttribute()) != UnknownRole)
-        return m_ariaRole;
+    m_ariaRole = determineAriaRoleAttribute();
+
+    AccessibilityRole ariaRole = ariaRoleAttribute();
+    if (ariaRole != UnknownRole)
+        return ariaRole;
 
     return RowRole;
 }