Use PASS() everywhere in ppapi/tests.

ppapi/tests/test_char_set.cc

 // Copyright (c) 2010 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 "ppapi/tests/test_char_set.h"
 
 #include "ppapi/c/dev/ppb_char_set_dev.h"
 #include "ppapi/cpp/module.h"
 #include "ppapi/tests/testing_instance.h"
 
@@ skipping 78 matching lines @@
               utf8result[2] == 0);
   pp::Module::Get()->core()->MemFree(utf8result);
 
   // Invalid encoding name.
   utf8result = char_set_interface_->UTF16ToCharSet(
       &utf16[0], static_cast<uint32_t>(utf16.size()), "poopiepants",
       PP_CHARSET_CONVERSIONERROR_SUBSTITUTE, &utf8result_len);
   ASSERT_TRUE(!utf8result);
   ASSERT_TRUE(utf8result_len == 0);
 
-  return std::string();
+  PASS();
 }
 
 std::string TestCharSet::TestCharSetToUTF16() {
   // Empty string.
   uint32_t utf16result_len;
   uint16_t* utf16result = char_set_interface_->CharSetToUTF16(
       "", 0, "latin1", PP_CHARSET_CONVERSIONERROR_FAIL, &utf16result_len);
   ASSERT_TRUE(utf16result);
   ASSERT_TRUE(utf16result_len == 0);
   ASSERT_TRUE(utf16result[0] == 0);
@@ skipping 31 matching lines @@
   ASSERT_TRUE(utf16result[0] == 'A' && utf16result[1] == 0xFFFD &&
               utf16result[2] == 'Z' && utf16result[3] == 0);
 
   // Invalid encoding name.
   utf16result = char_set_interface_->CharSetToUTF16(
       badutf8, 3, "poopiepants",
       PP_CHARSET_CONVERSIONERROR_SUBSTITUTE, &utf16result_len);
   ASSERT_TRUE(!utf16result);
   ASSERT_TRUE(utf16result_len == 0);
 
-  return std::string();
+  PASS();
 }
 
 std::vector<uint16_t> TestCharSet::UTF8ToUTF16(const std::string& utf8) {
   uint32_t result_len = 0;
   uint16_t* result = char_set_interface_->CharSetToUTF16(
       utf8.c_str(), static_cast<uint32_t>(utf8.size()),
       "utf-8", PP_CHARSET_CONVERSIONERROR_FAIL, &result_len);
 
   std::vector<uint16_t> result_vector;
   if (!result)
     return result_vector;
 
   result_vector.assign(result, &result[result_len]);
   pp::Module::Get()->core()->MemFree(result);
   return result_vector;
 }