Forward BrowserAccessibilityWin::get_accName to platform node.

BUG=703369

Review-Url: https://codereview.chromium.org/2855463003
Cr-Commit-Position: refs/heads/master@{#468422}

content/browser/accessibility/browser_accessibility_win.cc

@@ -659,29 +659,7 @@ STDMETHODIMP BrowserAccessibilityWin::get_accName(VARIANT var_id, BSTR* name) {
   if (!instance_active())
     return E_FAIL;
 
-  if (!name)
-    return E_INVALIDARG;
-
-  BrowserAccessibilityWin* target = GetTargetFromChildID(var_id);
-  if (!target)
-    return E_INVALIDARG;
-
-  base::string16 name_str = target->name();
-  if (name_str.empty()) {
-    if (target->ia2_role() == ROLE_SYSTEM_DOCUMENT && PlatformGetParent()) {
-      // Hack: Some versions of JAWS crash if they get an empty name on
-      // a document that's the child of an iframe, so always return a
-      // nonempty string for this role.  https://crbug.com/583057
-      name_str = L" ";
-    } else {
-      return S_FALSE;
-    }
-  }
-
-  *name = SysAllocString(name_str.c_str());
-
-  DCHECK(*name);
-  return S_OK;
+  return GetPlatformNodeWin()->get_accName(var_id, name);
 }
 
 STDMETHODIMP BrowserAccessibilityWin::get_accParent(IDispatch** disp_parent) {

ui/accessibility/platform/ax_platform_node_win.cc

@@ -474,7 +474,17 @@ STDMETHODIMP AXPlatformNodeWin::get_accName(
   AXPlatformNodeWin* target;
   COM_OBJECT_VALIDATE_VAR_ID_1_ARG_AND_GET_TARGET(var_id, name, target);
 
-  return target->GetStringAttributeAsBstr(ui::AX_ATTR_NAME, name);
+  HRESULT result = target->GetStringAttributeAsBstr(ui::AX_ATTR_NAME, name);
+  if (FAILED(result) && MSAARole() == ROLE_SYSTEM_DOCUMENT && GetParent()) {
+    // Hack: Some versions of JAWS crash if they get an empty name on
+    // a document that's the child of an iframe, so always return a
+    // nonempty string for this role.  https://crbug.com/583057
+    base::string16 str = L" ";
+
+    *name = SysAllocString(str.c_str());
+    DCHECK(*name);
+  }
+  return result;
 }
 
 STDMETHODIMP AXPlatformNodeWin::get_accParent(