Trivial: Language detection: avoid unsigned to signed conversion.

Removing usage of unsigned integer types in language detection to
comply with style guide.

R=dmazzoni,meredithl
CC=thestig

Change-Id: Ibeed71088a0ed4239f4d3c0aab8acc34b55687a1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2096603Reviewed-by: Meredith Lane <meredithl@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Chris Hall <chrishall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#753081}

ui/accessibility/ax_language_detection.cc

@@ -57,7 +57,7 @@ void AXLanguageInfoStats::Add(const std::vector<std::string>& languages) {
 
   // Assign languages with higher probability a higher score.
   // TODO(chrishall): consider more complex scoring
-  unsigned int score = kMaxDetectedLanguagesPerSpan;
+  int score = kMaxDetectedLanguagesPerSpan;
   for (const auto& lang : languages) {
     lang_counts_[lang] += score;
 

ui/accessibility/ax_language_detection.h

@@ -150,11 +150,11 @@ class AX_EXPORT AXLanguageInfoStats {
   friend class AXLanguageDetectionTestFixture;
 
   // Store a count of the occurrences of a given language.
-  std::unordered_map<std::string, unsigned int> lang_counts_;
+  std::unordered_map<std::string, int> lang_counts_;
 
   // Cache of last calculated top language results.
   // A vector of pairs of (score, language) sorted by descending score.
-  std::vector<std::pair<unsigned int, std::string>> top_results_;
+  std::vector<std::pair<int, std::string>> top_results_;
 
   // Boolean recording that we have not mutated the statistics since last
   // calculating top results, setting this to false will cause recalculation