Fix some grammar in content/common and content/public

content/public/browser/web_contents_delegate.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_DELEGATE_H_
 #define CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_DELEGATE_H_
 #pragma once
 
 #include <set>
 #include <string>
@@ skipping 160 matching lines @@
 
   // Invoked prior to showing before unload handler confirmation dialog.
   virtual void WillRunBeforeUnloadConfirm() {}
 
   // Returns true if javascript dialogs and unload alerts are suppressed.
   // Default is false.
   virtual bool ShouldSuppressDialogs();
 
   // Tells us that we've finished firing this tab's beforeunload event.
   // The proceed bool tells us whether the user chose to proceed closing the
-  // tab. Returns true if the tab can continue on firing it's unload event.
+  // tab. Returns true if the tab can continue on firing its unload event.
   // If we're closing the entire browser, then we'll want to delay firing
   // unload events until all the beforeunload events have fired.
   virtual void BeforeUnloadFired(WebContents* tab,
                                  bool proceed,
                                  bool* proceed_to_fire_unload);
 
   // Sets focus to the location bar or some other place that is appropriate.
   // This is called when the tab wants to encourage user input, like for the
   // new tab page.
   virtual void SetFocusToLocationBar(bool select_all) {}
@@ skipping 212 matching lines @@
   // Called when |this| is no longer the WebContentsDelegate for |source|.
   void Detach(WebContents* source);
 
   // The WebContents that this is currently a delegate for.
   std::set<WebContents*> attached_contents_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_DELEGATE_H_