Change other usages of .size() to .empty() when applicable.

chrome/browser/renderer_host/web_cache_manager.cc

Index: chrome/browser/renderer_host/web_cache_manager.cc
diff --git a/chrome/browser/renderer_host/web_cache_manager.cc b/chrome/browser/renderer_host/web_cache_manager.cc
index a555207f47fcb355e95a344e65f9da938e885c29..d422c33edb7d129a742b7fa05bc471442ae9e0fb 100644
--- a/chrome/browser/renderer_host/web_cache_manager.cc
+++ b/chrome/browser/renderer_host/web_cache_manager.cc
@@ -232,7 +232,7 @@ bool WebCacheManager::AttemptTactic(
   // The inactive renderers get one share of the extra memory to be divided
   // among themselves.
   size_t inactive_extra = 0;
-  if (inactive_renderers_.size() > 0) {
+  if (!inactive_renderers_.empty()) {
     ++shares;
     inactive_extra = total_extra / shares;
   }