Correctly record "No logo today" instead of "Parsing error"

components/search_provider_logos/google_logo_api.cc

 // Copyright 2014 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.
 
 #include "components/search_provider_logos/google_logo_api.h"
 
 #include <stdint.h>
 
 #include <algorithm>
 
@@ skipping 53 matching lines @@
   //     "url": "http://www.google.com/logos/doodle.png",
   //     "alt": "Wilbur Christiansen's Birthday"
   //     "time_to_live": 1389304799
   //   }}}
 
   // The response may start with )]}'. Ignore this.
   base::StringPiece response_sp(*response);
   if (response_sp.starts_with(kResponsePreamble))
     response_sp.remove_prefix(strlen(kResponsePreamble));
 
-  scoped_ptr<base::Value> value = base::JSONReader::Read(response_sp);
-
-  // Check if no logo today.
-  if (!value.get()) {
-    *parsing_failed = false;
-    return scoped_ptr<EncodedLogo>();
-  }
-
   // Default parsing failure to be true.
   *parsing_failed = true;

[newt (away), 2016/01/22 03:11:20]

I'd move this line to very beginning of the function now. (or at least, after
the initial implementation comment)

+  scoped_ptr<base::Value> value = base::JSONReader::Read(response_sp);
+  if (!value.get())
+    return scoped_ptr<EncodedLogo>();
   // The important data lives inside several nested dictionaries:
   // {"update": {"logo": { "mime_type": ..., etc } } }
   const base::DictionaryValue* outer_dict;
   if (!value->GetAsDictionary(&outer_dict))
     return scoped_ptr<EncodedLogo>();
   const base::DictionaryValue* update_dict;
   if (!outer_dict->GetDictionary("update", &update_dict))
     return scoped_ptr<EncodedLogo>();
+
+  // If there is no logo today, the server sends out an empty update.

[newt (away), 2016/01/22 03:11:20]

Slightly less ambiguous, I think: "If there is no logo today, the "update"
dictionary will be empty."

+  if (update_dict->empty()) {
+    *parsing_failed = false;
+    return scoped_ptr<EncodedLogo>();
+  }
+
   const base::DictionaryValue* logo_dict;
   if (!update_dict->GetDictionary("logo", &logo_dict))
     return scoped_ptr<EncodedLogo>();
 
   scoped_ptr<EncodedLogo> logo(new EncodedLogo());
 
   std::string encoded_image_base64;
   if (logo_dict->GetString("data", &encoded_image_base64)) {
     // Data is optional, since we may be revalidating a cached logo.
     base::RefCountedString* encoded_image_string = new base::RefCountedString();
@@ skipping 25 matching lines @@
     logo->metadata.can_show_after_expiration = true;
   }
   logo->metadata.expiration_time = response_time + time_to_live;
 
   // If this point is reached, parsing has succeeded.
   *parsing_failed = false;
   return logo;
 }
 
 }  // namespace search_provider_logos