Convert string16 to base::string16 in content.

content/shell/browser/shell.h

Index: content/shell/browser/shell.h
diff --git a/content/shell/browser/shell.h b/content/shell/browser/shell.h
index 20515f69226d9158304c81414c695ffe03aae075..1434b76c1194047d70cd4aa959951165969c0cd1 100644
--- a/content/shell/browser/shell.h
+++ b/content/shell/browser/shell.h
@@ -142,9 +142,9 @@ class Shell : public WebContentsDelegate,
 #endif
   virtual bool AddMessageToConsole(WebContents* source,
                                    int32 level,
-                                   const string16& message,
+                                   const base::string16& message,
                                    int32 line_no,
-                                   const string16& source_id) OVERRIDE;
+                                   const base::string16& source_id) OVERRIDE;
   virtual void RendererUnresponsive(WebContents* source) OVERRIDE;
   virtual void ActivateContents(WebContents* contents) OVERRIDE;
   virtual void DeactivateContents(WebContents* contents) OVERRIDE;
@@ -191,7 +191,7 @@ class Shell : public WebContentsDelegate,
   // Sets whether the spinner is spinning.
   void PlatformSetIsLoading(bool loading);
   // Set the title of shell window
-  void PlatformSetTitle(const string16& title);
+  void PlatformSetTitle(const base::string16& title);
 #if defined(OS_ANDROID)
   void PlatformToggleFullscreenModeForTab(WebContents* web_contents,
                                           bool enter_fullscreen);