[Coverity] Fixed call by value to by reference

content/common/net/url_fetcher_impl.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 "content/common/net/url_fetcher_impl.h"
 
 #include <set>
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
@@ skipping 96 matching lines @@
   class TempFileWriter {
    public:
     TempFileWriter(
         URLFetcherImpl::Core* core,
         scoped_refptr<base::MessageLoopProxy> file_message_loop_proxy);
 
     ~TempFileWriter();
     void CreateTempFile();
     void DidCreateTempFile(base::PlatformFileError error_code,
                            base::PassPlatformFile file_handle,
-                           FilePath file_path);
+                           const FilePath& file_path);
 
     // Record |num_bytes_| response bytes in |core_->buffer_| to the file.
     void WriteBuffer(int num_bytes);
 
     // Called when a write has been done.  Continues writing if there are
     // any more bytes to write.  Otherwise, initiates a read in core_.
     void ContinueWrite(base::PlatformFileError error_code,
                        int bytes_written);
 
     // Drop ownership of the file at path |temp_file_|. This class
@@ skipping 210 matching lines @@
   base::FileUtilProxy::CreateTemporary(
       file_message_loop_proxy_,
       0,  // No additional file flags.
       base::Bind(&URLFetcherImpl::Core::TempFileWriter::DidCreateTempFile,
                  weak_factory_.GetWeakPtr()));
 }
 
 void URLFetcherImpl::Core::TempFileWriter::DidCreateTempFile(
     base::PlatformFileError error_code,
     base::PassPlatformFile file_handle,
-    FilePath file_path) {
+    const FilePath& file_path) {
   DCHECK(core_->io_message_loop_proxy_->BelongsToCurrentThread());
 
   if (base::PLATFORM_FILE_OK != error_code) {
     error_code_ = error_code;
     RemoveTempFile();
     core_->delegate_loop_proxy_->PostTask(
         FROM_HERE, base::Bind(&Core::InformDelegateFetchIsComplete, core_));
     return;
   }
 
@@ skipping 766 matching lines @@
 
 // static
 content::URLFetcherFactory* URLFetcherImpl::factory() {
   return g_factory;
 }
 
 // static
 void URLFetcherImpl::set_factory(content::URLFetcherFactory* factory) {
   g_factory = factory;
 }