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

content/browser/dom_storage/dom_storage_area.cc

Index: content/browser/dom_storage/dom_storage_area.cc
diff --git a/content/browser/dom_storage/dom_storage_area.cc b/content/browser/dom_storage/dom_storage_area.cc
index 7bb96f34564f1d9b7225d4b4b4e7bb237f4a631d..81c2be745d637f0256e1140804ba3ec1cdb77dc7 100644
--- a/content/browser/dom_storage/dom_storage_area.cc
+++ b/content/browser/dom_storage/dom_storage_area.cc
@@ -4,6 +4,8 @@
 
 #include "content/browser/dom_storage/dom_storage_area.h"
 
+#include <inttypes.h>
+
 #include <algorithm>
 #include <cctype>  // for std::isalnum
 
@@ -347,7 +349,9 @@ void DOMStorageArea::OnMemoryDump(base::trace_event::ProcessMemoryDump* pmd) {
     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()