Fix some grammar in chrome/browser/history

chrome/browser/history/text_database_manager.cc

Index: chrome/browser/history/text_database_manager.cc
diff --git a/chrome/browser/history/text_database_manager.cc b/chrome/browser/history/text_database_manager.cc
index 499e3e15cf526fc296428fbe09f3c14d2992e5ae..816499969374c5c8b4a3ebda949c2902b918dbeb 100644
--- a/chrome/browser/history/text_database_manager.cc
+++ b/chrome/browser/history/text_database_manager.cc
@@ -237,7 +237,7 @@ void TextDatabaseManager::AddPageContents(const GURL& url,
     // This page is not in our cache of recent pages. This means that the page
     // took more than kExpirationSeconds to load. Often, this will be the result
     // of a very slow iframe or other resource on the page that makes us think
-    // its still loading.
+    // it's still loading.
     //
     // As a fallback, set the most recent visit's contents using the input, and
     // use the last set title in the URL table as the title to index.