Cache User Agent string in BlinkPlatformImpl

content/public/common/content_client.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_COMMON_CONTENT_CLIENT_H_
 #define CONTENT_PUBLIC_COMMON_CONTENT_CLIENT_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 83 matching lines @@
       std::vector<std::string>* savable_schemes) {}
 
   // Returns whether the given message should be sent in a swapped out renderer.
   virtual bool CanSendWhileSwappedOut(const IPC::Message* message);
 
   // Returns a string describing the embedder product name and version,
   // of the form "productname/version", with no other slashes.
   // Used as part of the user agent string.
   virtual std::string GetProduct() const;
 
-  // Returns the user agent.
+  // Returns the user agent.  Content may cache this value.
   virtual std::string GetUserAgent() const;
 
   // Returns a string resource given its id.
   virtual base::string16 GetLocalizedString(int message_id) const;
 
   // Return the contents of a resource in a StringPiece given the resource id.
   virtual base::StringPiece GetDataResource(
       int resource_id,
       ui::ScaleFactor scale_factor) const;
 
@@ skipping 49 matching lines @@
   ContentPluginClient* plugin_;
   // The embedder API for participating in renderer logic.
   ContentRendererClient* renderer_;
   // The embedder API for participating in utility logic.
   ContentUtilityClient* utility_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_CONTENT_CLIENT_H_