Fix uninitialized read in the SimpleCache tests.

net/disk_cache/entry_unittest.cc

 // Copyright (c) 2012 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 "base/basictypes.h"
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/file_util.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
@@ skipping 2835 matching lines @@
   disk_cache::Entry* entry = NULL;
 
   // First, an optimistic create.
   ASSERT_EQ(net::OK,
             cache_->CreateEntry(key, &entry, net::CompletionCallback()));
 
   ASSERT_TRUE(entry);
   const int kWriteSize = 512;
   scoped_refptr<net::IOBuffer> buffer1(new net::IOBuffer(kWriteSize));
   EXPECT_TRUE(buffer1->HasOneRef());
+  CacheTestFillBuffer(buffer1->data(), kWriteSize, false);
 
   // An optimistic write happens only when there is an empty queue of pending
   // operations. To ensure the queue is empty, we issue a write and wait until
   // it completes.
   EXPECT_EQ(kWriteSize,
             WriteData(entry, 0, 0, buffer1, kWriteSize, false));
   EXPECT_TRUE(buffer1->HasOneRef());
 
   // Finally, we should perform an optimistic write and confirm that all
   // references to the IO buffer have been released.
@@ skipping 253 matching lines @@
   net::TestCompletionCallback cb2;
   int rv1 = cache_->OpenEntry("key", &entry1, cb1.callback());
   int rv2 = cache_->CreateEntry("key", &entry2, cb2.callback());
 
   ASSERT_EQ(net::OK, cb2.GetResult(rv2));
   EXPECT_EQ(net::ERR_FAILED, cb1.GetResult(rv1));
   entry2->Close();
 }
 
 #endif  // defined(OS_POSIX)