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

chrome/browser/extensions/extension_updater_unittest.cc

 // Copyright (c) 2011 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 <map>
 
 #include "base/file_util.h"
 #include "base/scoped_ptr.h"
 #include "base/stl_util-inl.h"
 #include "base/string_number_conversions.h"
@@ skipping 261 matching lines @@
 // puts the key/value pairs into |result|. For keys with no value, the empty
 // string is used. So for "a=1&b=foo&c", result would map "a" to "1", "b" to
 // "foo", and "c" to "".
 static void ExtractParameters(const std::string& params,
                               std::map<std::string, std::string>* result) {
   std::vector<std::string> pairs;
   base::SplitString(params, '&', &pairs);
   for (size_t i = 0; i < pairs.size(); i++) {
     std::vector<std::string> key_val;
     base::SplitString(pairs[i], '=', &key_val);
-    if (key_val.size() > 0) {
+    if (!key_val.empty()) {
       std::string key = key_val[0];
       EXPECT_TRUE(result->find(key) == result->end());
       (*result)[key] = (key_val.size() == 2) ? key_val[1] : "";
     } else {
       NOTREACHED();
     }
   }
 }
 
 // All of our tests that need to use private APIs of ExtensionUpdater live
@@ skipping 776 matching lines @@
 
 // TODO(asargent) - (http://crbug.com/12780) add tests for:
 // -prodversionmin (shouldn't update if browser version too old)
 // -manifests & updates arriving out of order / interleaved
 // -malformed update url (empty, file://, has query, has a # fragment, etc.)
 // -An extension gets uninstalled while updates are in progress (so it doesn't
 //  "come back from the dead")
 // -An extension gets manually updated to v3 while we're downloading v2 (ie
 //  you don't get downgraded accidentally)
 // -An update manifest mentions multiple updates