Revert of Remove WindowFocusAllowedIndicator and associated code.

Source/web/tests/WebScopedWindowFocusAllowedIndicatorTest.cpp

Index: Source/web/tests/WebScopedWindowFocusAllowedIndicatorTest.cpp
diff --git a/Source/web/tests/WebScopedWindowFocusAllowedIndicatorTest.cpp b/Source/web/tests/WebScopedWindowFocusAllowedIndicatorTest.cpp
index a09cfd186a919d01d2df12a80261e572f51fc40c..970a542ab0fde1cd025bb0488307c6f49ce64818 100644
--- a/Source/web/tests/WebScopedWindowFocusAllowedIndicatorTest.cpp
+++ b/Source/web/tests/WebScopedWindowFocusAllowedIndicatorTest.cpp
@@ -32,6 +32,7 @@
 #include "public/web/WebScopedWindowFocusAllowedIndicator.h"
 
 #include "core/dom/Document.h"
+#include "core/page/WindowFocusAllowedIndicator.h"
 #include "public/web/WebDocument.h"
 #include <gtest/gtest.h>
 
@@ -40,6 +41,21 @@
 namespace {
 
 TEST(WebScopedWindowFocusAllowedIndicatorTest, Basic)
+{
+    EXPECT_FALSE(WindowFocusAllowedIndicator::windowFocusAllowed());
+    {
+        WebScopedWindowFocusAllowedIndicator indicator1;
+        EXPECT_TRUE(WindowFocusAllowedIndicator::windowFocusAllowed());
+        {
+            WebScopedWindowFocusAllowedIndicator indicator2;
+            EXPECT_TRUE(WindowFocusAllowedIndicator::windowFocusAllowed());
+        }
+        EXPECT_TRUE(WindowFocusAllowedIndicator::windowFocusAllowed());
+    }
+    EXPECT_FALSE(WindowFocusAllowedIndicator::windowFocusAllowed());
+}
+
+TEST(WebScopedWindowFocusAllowedIndicatorTest, WithDocument)
 {
     RefPtrWillBePersistent<Document> document = Document::create();
     WebDocument webDocument(document);