Use PASS() everywhere in ppapi/tests.

ppapi/tests/test_buffer.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_buffer.h"
 
 #include "ppapi/c/dev/ppb_buffer_dev.h"
 #include "ppapi/cpp/dev/buffer_dev.h"
 #include "ppapi/cpp/graphics_2d.h"
 #include "ppapi/cpp/instance.h"
@@ skipping 12 matching lines @@
   instance_->LogTest("InvalidSize", TestInvalidSize());
   instance_->LogTest("InitToZero", TestInitToZero());
   instance_->LogTest("IsBuffer", TestIsBuffer());
 }
 
 std::string TestBuffer::TestInvalidSize() {
   pp::Buffer_Dev zero_size(0);
   if (!zero_size.is_null())
     return "Zero size accepted";
 
-  return "";
+  PASS();
 }
 
 std::string TestBuffer::TestInitToZero() {
   pp::Buffer_Dev buffer(100);
   if (buffer.is_null())
     return "Could not create buffer";
 
   if (buffer.size() != 100)
     return "Buffer size not as expected";
 
   // Now check that everything is 0.
   unsigned char* bytes = static_cast<unsigned char *>(buffer.data());
   for (uint32_t index = 0; index < buffer.size(); index++) {
     if (bytes[index] != 0)
       return "Buffer isn't entirely zero";
   }
 
-  return "";
+  PASS();
 }
 
 std::string TestBuffer::TestIsBuffer() {
   // Test that a NULL resource isn't a buffer.
   pp::Resource null_resource;
   if (buffer_interface_->IsBuffer(null_resource.pp_resource()))
     return "Null resource was reported as a valid buffer";
 
   // Make another resource type and test it.
   const int w = 16, h = 16;
   pp::Graphics2D device(pp::Size(w, h), true);
   if (device.is_null())
     return "Couldn't create device context";
   if (buffer_interface_->IsBuffer(device.pp_resource()))
     return "Device context was reported as a buffer";
 
   // Make a valid buffer.
   pp::Buffer_Dev buffer(100);
   if (buffer.is_null())
     return "Couldn't create buffer";
   if (!buffer_interface_->IsBuffer(buffer.pp_resource()))
     return "Buffer should be identified as a buffer";
 
-  return "";
+  PASS();
 }