Move user_agent code from webkit/ to content/.

content/public/common/content_client.h

Index: content/public/common/content_client.h
diff --git a/content/public/common/content_client.h b/content/public/common/content_client.h
index 1695656e891feb41918cb34c0b7e678361ae6b28..5aba3b6773d929b97bfebbba5f362a3ea7c9e209 100644
--- a/content/public/common/content_client.h
+++ b/content/public/common/content_client.h
@@ -65,16 +65,6 @@ CONTENT_EXPORT ContentRendererClient* SetRendererClientForTesting(
 CONTENT_EXPORT ContentUtilityClient* SetUtilityClientForTesting(
     ContentUtilityClient* u);
 
-// Returns the user agent string being used by the browser. SetContentClient()
-// must be called prior to calling this, and this routine must be used
-// instead of webkit_glue::GetUserAgent() in order to ensure that we use
-// the same user agent string everywhere.
-// TODO(dpranke): This is caused by webkit_glue being a library that can
-// get linked into multiple linkable objects, causing us to have multiple
-// static values of the user agent. This will be fixed when we clean up
-// webkit_glue.
-CONTENT_EXPORT const std::string& GetUserAgent(const GURL& url);
-
 // Interface that the embedder implements.
 class CONTENT_EXPORT ContentClient {
  public: