Declare a variable before using it

components/autofill/core/browser/personal_data_manager.cc

Index: components/autofill/core/browser/personal_data_manager.cc
diff --git a/components/autofill/core/browser/personal_data_manager.cc b/components/autofill/core/browser/personal_data_manager.cc
index 590f814d6073c07ed0ea15fb6515ecb2bb0dbd9d..af62c8548cc24498ae51862960c1190a67bfe488 100644
--- a/components/autofill/core/browser/personal_data_manager.cc
+++ b/components/autofill/core/browser/personal_data_manager.cc
@@ -880,7 +880,9 @@ std::vector<Suggestion> PersonalDataManager::GetProfileSuggestions(
   // trial group or SIZE_MAX if no limit is defined.
   std::string limit_str = variations::GetVariationParamValue(
       kFrecencyFieldTrialName, kFrecencyFieldTrialLimitParam);
-  size_t limit = base::StringToSizeT(limit_str, &limit) ? limit : SIZE_MAX;
+  size_t limit;

[vabr (Chromium), 2017/03/04 19:40:29]

This is actually worse than before. Before there was not a single point in the
code where |limit| would not be initialised. Now the declaration and assignment
are separate, and if somebody adds code between them, there will be a
non-trivial interval of |limit| having an undefined value.

Please either revert to the previous state, or initialize limit. A good default
value is SIZE_MAX. Note that you also still need to keep the assignment after
calling StringToSizeT, because that method can modify |limit| even if it returns
false. This would be good to capture in a comment here as well.

size_t limit = SIZE_MAX;

[chengx, 2017/03/06 18:26:14]

I will use another CL to fix this. Thanks!

[vabr (Chromium), 2017/03/06 18:46:48]

SGTM, thanks for following up! :)

+  if (!base::StringToSizeT(limit_str, &limit))
+    limit = SIZE_MAX;
 
   unique_suggestions.resize(std::min(unique_suggestions.size(), limit));