Make the profile buffer larger in third_party/tcmalloc/chromium.

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

Index: third_party/tcmalloc/chromium/src/heap-profiler.cc
diff --git a/third_party/tcmalloc/chromium/src/heap-profiler.cc b/third_party/tcmalloc/chromium/src/heap-profiler.cc
index fd0faa33fdf486dca69ee09f51f9254b42373339..0821a657737430e83a00d159264f7dadf42f934e 100644
--- a/third_party/tcmalloc/chromium/src/heap-profiler.cc
+++ b/third_party/tcmalloc/chromium/src/heap-profiler.cc
@@ -149,7 +149,9 @@ static void ProfilerFree(void* p) {
 }
 
 // We use buffers of this size in DoGetHeapProfile.
-static const int kProfileBufferSize = 1 << 20;
+// The size is 1 << 20 in the original google-perftools.  Changed it to
+// 5 << 20 since larger buffers are requried for deeper profiling in Chromium.

[jar (doing other things), 2011/12/22 16:02:09]

Could you provide a comment that makes it clear when this amount of memory is
allocated and used? 1 Meg is already a lot, and 5M is of course a whole lot.

I started to read the code to try to track this down, but IMO, it would be nice
to have the comment here.

[Dai Mikurube (NOT FULLTIME), 2011/12/26 03:58:26]

Done.

+static const int kProfileBufferSize = 5 << 20;
 
 // This is a last-ditch buffer we use in DumpProfileLocked in case we
 // can't allocate more memory from ProfilerMalloc.  We expect this