[tracing] Replace %p with %PRIXPTR in the memory dump names

content/browser/dom_storage/dom_storage_area.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/browser/dom_storage/dom_storage_area.h"
 
+#include <inttypes.h>
+
 #include <algorithm>
 #include <cctype>  // for std::isalnum
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/process/process_info.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 323 matching lines @@
   DCHECK(task_runner_->IsRunningOnPrimarySequence());
   if (!is_initial_import_done_)
     return;
 
   // Limit the url length to 50 and strip special characters.
   std::string url = origin_.spec().substr(0, 50);
   for (size_t index = 0; index < url.size(); ++index) {
     if (!std::isalnum(url[index]))
       url[index] = '_';
   }
-  std::string name = StringPrintf("dom_storage/%s/%p", url.c_str(), this);
+  std::string name =
+      base::StringPrintf("dom_storage/%s/0x%" PRIXPTR, url.c_str(),

[Primiano Tucci (use gerrit), 2016/06/14 08:33:51]

uh, how is this working today without base? cannot find anything doing using
StringPrintf? To be clear, your +base:: looks good but I am struggling to figure
out how this did compile before?

[ssid, 2016/06/14 20:28:15]

So, we figured that C++ adds the namespaces of the arguments passed to function
call to the search space for the function. But, the arguments passed here are
just "this" pointer and DOMStorageArea class is not part of base namespace. But,
it does inherit from a class from base (base::RefCountedThreadSafe), so base::
is added into the search space.
Now it stopped compiling because the argument this is no longer passed.
C++ is magic!

Note that no file that this file includes has a definition of using
base::StringPrintf. But the above explanation seems to hold with various other
test cases.

+                         reinterpret_cast<uintptr_t>(this));
 
   const char* system_allocator_name =
       base::trace_event::MemoryDumpManager::GetInstance()
           ->system_allocator_pool_name();
   if (commit_batch_) {
     auto commit_batch_mad = pmd->CreateAllocatorDump(name + "/commit_batch");
     commit_batch_mad->AddScalar(
         base::trace_event::MemoryAllocatorDump::kNameSize,
         base::trace_event::MemoryAllocatorDump::kUnitsBytes,
         commit_batch_->GetDataSize());
@@ skipping 159 matching lines @@
         commit_batch_->clear_all_first,
         commit_batch_->changed_values);
     DCHECK(success);
   }
   commit_batch_.reset();
   backing_.reset();
   session_storage_backing_ = NULL;
 }
 
 }  // namespace content