Tracing: fix error checking from deflate() when compressing trace

content/browser/tracing/tracing_controller_impl_data_sinks.cc

 // Copyright 2015 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 <utility>
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
 #include "base/json/json_writer.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
@@ skipping 234 matching lines @@
   void DrainStreamOnFileThread(bool finished) {
     DCHECK_CURRENTLY_ON(BrowserThread::FILE);
 
     int err;
     const int kChunkSize = 0x4000;
     char buffer[kChunkSize];
     do {
       stream_->avail_out = kChunkSize;
       stream_->next_out = (unsigned char*)buffer;
       err = deflate(stream_.get(), finished ? Z_FINISH : Z_NO_FLUSH);
-      if (err != (finished ? Z_STREAM_END : Z_OK)) {
+      if (err != Z_OK && (!finished || err != Z_STREAM_END)) {
+        LOG(ERROR) << "Deflate stream error: " << err;
         stream_.reset();
         return;
       }
 
       int bytes = kChunkSize - stream_->avail_out;
       if (bytes) {
         std::string compressed(buffer, bytes);
         endpoint_->ReceiveTraceChunk(base::MakeUnique<std::string>(compressed));
       }
     } while (stream_->avail_out == 0);
@@ skipping 64 matching lines @@
   return new JSONTraceDataSink(new CompressedTraceDataEndpoint(endpoint));
 }
 
 scoped_refptr<TraceDataEndpoint> TracingControllerImpl::CreateCallbackEndpoint(
     const base::Callback<void(std::unique_ptr<const base::DictionaryValue>,
                               base::RefCountedString*)>& callback) {
   return new StringTraceDataEndpoint(callback);
 }
 
 }  // namespace content