Ensure autorelease pool is drained between tests

The testing::Test fixture (used by TEST macro) does not drain the
autorelease pool after a test. PlatformTest should be used.

Bug: none
Change-Id: I7b33f0c53bc57fb8f2266bc58eb578d71da642b4
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Reviewed-on: https://chromium-review.googlesource.com/940132
Commit-Queue: Olivier Robin <[email protected]>
Reviewed-by: Olivier Robin <[email protected]>
Cr-Commit-Position: refs/heads/master@{#539798}
diff --git a/ios/net/chunked_data_stream_uploader_unittest.cc b/ios/net/chunked_data_stream_uploader_unittest.cc
index 48f62c8..64996b0 100644
--- a/ios/net/chunked_data_stream_uploader_unittest.cc
+++ b/ios/net/chunked_data_stream_uploader_unittest.cc
@@ -10,6 +10,7 @@
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "testing/platform_test.h"
 
 namespace net {
 
@@ -47,7 +48,7 @@
   int data_length_;
 };
 
-class ChunkedDataStreamUploaderTest : public testing::Test {
+class ChunkedDataStreamUploaderTest : public PlatformTest {
  public:
   ChunkedDataStreamUploaderTest() : callback_count(0) {
     delegate_ = std::make_unique<MockChunkedDataStreamUploaderDelegate>();