Fix ATK hyperlink action castings.

This is a fix for a regression introduced by this jumbo fix:
    commit b1622826
    Author: Mostyn Bramley-Moore <mostynb@vewd.com>
    Date:   Wed Nov 15 07:05:13 2017 +0000

    [jumbo] avoid ToBrowserAccessibilityAuraLinux redefinition

The change reuses the BrowserAccessibilityAuraLinux AtkAction
casting for BrowserAccessibilityAtkHyperlink. But it is not the
same object, and it will break the hyperlink action support. So
let's provide again a specific casting, but with a name that will
not clash with jumbo build.

Bug: 783447
Change-Id: I319154aadd5aa040a2222d533ca94cb83877068e
Reviewed-on: https://chromium-review.googlesource.com/776778Reviewed-by: Mostyn Bramley-Moore <mostynb@vewd.com>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: José Dapena Paz <jose.dapena@lge.com>
Cr-Commit-Position: refs/heads/master@{#517484}

content/browser/accessibility/browser_accessibility_atk_hyperlink.cc

@@ -101,12 +101,22 @@ static void browser_accessibility_atk_hyperlink_class_init(
 // AtkAction interface.
 //
 
+static BrowserAccessibilityAuraLinux*
+ToBrowserAccessibilityAuraLinuxFromHyperlinkAction(AtkAction* atk_action) {
+  if (!IS_BROWSER_ACCESSIBILITY_ATK_HYPERLINK(atk_action))
+    return nullptr;
+
+  return ToBrowserAccessibilityAuraLinux(
+      BROWSER_ACCESSIBILITY_ATK_HYPERLINK(atk_action));
+}
+
 static gboolean browser_accessibility_atk_hyperlink_do_action(AtkAction* action,
                                                               gint index) {
   g_return_val_if_fail(ATK_IS_ACTION(action), FALSE);
   g_return_val_if_fail(!index, FALSE);
 
-  BrowserAccessibilityAuraLinux* obj = ToBrowserAccessibilityAuraLinux(action);
+  BrowserAccessibilityAuraLinux* obj =
+      ToBrowserAccessibilityAuraLinuxFromHyperlinkAction(action);
   if (!obj)
     return FALSE;
 
@@ -119,7 +129,8 @@ static gint browser_accessibility_atk_hyperlink_get_n_actions(
     AtkAction* action) {
   g_return_val_if_fail(ATK_IS_ACTION(action), FALSE);
 
-  BrowserAccessibilityAuraLinux* obj = ToBrowserAccessibilityAuraLinux(action);
+  BrowserAccessibilityAuraLinux* obj =
+      ToBrowserAccessibilityAuraLinuxFromHyperlinkAction(action);
   if (!obj)
     return 0;
 
@@ -132,7 +143,8 @@ static const gchar* browser_accessibility_atk_hyperlink_get_description(
   g_return_val_if_fail(ATK_IS_ACTION(action), FALSE);
   g_return_val_if_fail(!index, FALSE);
 
-  BrowserAccessibilityAuraLinux* obj = ToBrowserAccessibilityAuraLinux(action);
+  BrowserAccessibilityAuraLinux* obj =
+      ToBrowserAccessibilityAuraLinuxFromHyperlinkAction(action);
   if (!obj)
     return nullptr;
 
@@ -146,7 +158,8 @@ static const gchar* browser_accessibility_atk_hyperlink_get_keybinding(
   g_return_val_if_fail(ATK_IS_ACTION(action), FALSE);
   g_return_val_if_fail(!index, FALSE);
 
-  BrowserAccessibilityAuraLinux* obj = ToBrowserAccessibilityAuraLinux(action);
+  BrowserAccessibilityAuraLinux* obj =
+      ToBrowserAccessibilityAuraLinuxFromHyperlinkAction(action);
   if (!obj)
     return nullptr;
 
@@ -160,7 +173,7 @@ static const gchar* browser_accessibility_atk_hyperlink_get_name(
   g_return_val_if_fail(!index, FALSE);
 
   BrowserAccessibilityAuraLinux* obj =
-      ToBrowserAccessibilityAuraLinux(atk_action);
+      ToBrowserAccessibilityAuraLinuxFromHyperlinkAction(atk_action);
   if (!obj)
     return nullptr;
 
@@ -179,7 +192,7 @@ static const gchar* browser_accessibility_atk_hyperlink_get_localized_name(
   g_return_val_if_fail(!index, FALSE);
 
   BrowserAccessibilityAuraLinux* obj =
-      ToBrowserAccessibilityAuraLinux(atk_action);
+      ToBrowserAccessibilityAuraLinuxFromHyperlinkAction(atk_action);
   if (!obj)
     return nullptr;