Add a checked_cast for size_t to uint32_t conversion.

content/child/webblobregistry_impl.cc

 // Copyright 2013 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/child/webblobregistry_impl.h"
 
 #include "base/files/file_path.h"
 #include "base/guid.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/shared_memory.h"
 #include "base/message_loop/message_loop.h"
+#include "base/numerics/safe_conversions.h"
 #include "base/trace_event/trace_event.h"
 #include "content/child/child_thread_impl.h"
 #include "content/child/thread_safe_sender.h"
 #include "content/common/fileapi/webblob_messages.h"
 #include "third_party/WebKit/public/platform/WebBlobData.h"
 #include "third_party/WebKit/public/platform/WebString.h"
 #include "third_party/WebKit/public/platform/WebThreadSafeData.h"
 #include "third_party/WebKit/public/platform/WebURL.h"
 
 using blink::WebBlobData;
@@ skipping 124 matching lines @@
     CHECK(shared_memory.get());
     if (!shared_memory->Map(shared_memory_size))
       CHECK(false);
 
     size_t remaining_bytes = length;
     const char* current_ptr = data;
     while (remaining_bytes) {
       size_t chunk_size = std::min(remaining_bytes, shared_memory_size);
       memcpy(shared_memory->memory(), current_ptr, chunk_size);
       sender_->Send(new StreamHostMsg_SyncAppendSharedMemory(
-          url, shared_memory->handle(), chunk_size));
+          url, shared_memory->handle(),
+          base::checked_cast<uint32_t>(chunk_size)));
       remaining_bytes -= chunk_size;
       current_ptr += chunk_size;
     }
   }
 }
 
 void WebBlobRegistryImpl::flushStream(const WebURL& url) {
   DCHECK(ChildThreadImpl::current());
   sender_->Send(new StreamHostMsg_Flush(url));
 }
@@ skipping 132 matching lines @@
     consolidation_.ReadMemory(consolidated_item_index, offset, chunk_size,
                               shared_memory->memory());
     sender_->Send(new BlobHostMsg_SyncAppendSharedMemory(
         uuid_, shared_memory->handle(), static_cast<uint32_t>(chunk_size)));
     data_size -= chunk_size;
     offset += chunk_size;
   }
 }
 
 }  // namespace content