Fix heap profiler to always append the process id to the heap dump.

To run Chrome:
HEAP_PROFILE_ALLOCATION_INTERVAL=1000000 HEAPPROFILE=heapprof out/Debug/chrome

To analyze:
pprof --text out/Debug/chrome  heapprof.21026.0039.heap
pprof --gv out/Debug/chrome  heapprof.21026.0039.heap
(pprof is slooow)
Review URL: http://codereview.chromium.org/6532051

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@86273 0039d316-1c4b-4281-b951-d872f2087c98

third_party/tcmalloc/chromium/src/base/sysinfo.cc

@@ -176,6 +176,9 @@ const char* GetenvBeforeMain(const char* name) {
 // in their first character!  If that assumption is violated, we'll
 // still get a profile, but one with an unexpected name.
 // TODO(csilvers): set an envvar instead when we can do it reliably.
+//
+// In Chromium this hack is intentionally disabled, because the path is not
+// re-initialized upon fork.
 bool GetUniquePathFromEnv(const char* env_name, char* path) {
   char* envval = getenv(env_name);
   if (envval == NULL || *envval == '\0')
@@ -185,7 +188,9 @@ bool GetUniquePathFromEnv(const char* env_name, char* path) {
              envval[0] & 127, envval+1, (unsigned int)(getpid()));
   } else {
     snprintf(path, PATH_MAX, "%s", envval);
+#if 0
     envval[0] |= 128;                     // set high bit for kids to see
+#endif
   }
   return true;
 }

third_party/tcmalloc/chromium/src/heap-profiler.cc

@@ -258,8 +258,8 @@ static void DumpProfileLocked(const char* reason) {
   // Make file name
   char file_name[1000];
   dump_count++;
-  snprintf(file_name, sizeof(file_name), "%s.%04d%s",
-           filename_prefix, dump_count, HeapProfileTable::kFileExt);
+  snprintf(file_name, sizeof(file_name), "%s.%05d.%04d%s",
+           filename_prefix, getpid(), dump_count, HeapProfileTable::kFileExt);
 
   // Dump the profile
   RAW_VLOG(0, "Dumping heap profile to %s (%s)", file_name, reason);