GTK: Implement BlockedPopupContainerView for linux.

chrome/browser/tab_contents/tab_contents.cc

Index: chrome/browser/tab_contents/tab_contents.cc
diff --git a/chrome/browser/tab_contents/tab_contents.cc b/chrome/browser/tab_contents/tab_contents.cc
index ad09bf6bea142284c90bf5fe2ca3e8ffd6ccc3b0..030a79f8a0cbb825aec27e92e993eb836287b9b2 100644
--- a/chrome/browser/tab_contents/tab_contents.cc
+++ b/chrome/browser/tab_contents/tab_contents.cc
@@ -769,8 +769,7 @@ void TabContents::AddNewContents(TabContents* new_contents,
   if (!delegate_)
     return;
 
-#if defined(OS_WIN)
-  bool constrain_popup = false;
+#if defined(OS_WIN) || defined(OS_LINUX)
   if ((disposition == NEW_POPUP) && !user_gesture &&
       !CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kDisablePopupBlocking)) {
@@ -1072,7 +1071,7 @@ void TabContents::SetIsLoading(bool is_loading,
       det);
 }
 
-#if defined(OS_WIN)
+#if defined(OS_WIN) || defined(OS_LINUX)
 void TabContents::CreateBlockedPopupContainerIfNecessary() {
   if (blocked_popups_)
     return;