Add the reason in heap profiler dumps.

third_party/tcmalloc/chromium/src/deep-heap-profile.cc

Index: third_party/tcmalloc/chromium/src/deep-heap-profile.cc
diff --git a/third_party/tcmalloc/chromium/src/deep-heap-profile.cc b/third_party/tcmalloc/chromium/src/deep-heap-profile.cc
index f89d8ce90e3c7d8f267aa2222be281cb9319fefa..ab57a186d5f12ddc4c5263d4b7d66458e85bf1e2 100644
--- a/third_party/tcmalloc/chromium/src/deep-heap-profile.cc
+++ b/third_party/tcmalloc/chromium/src/deep-heap-profile.cc
@@ -229,7 +229,9 @@ DeepHeapProfile::~DeepHeapProfile() {
 
 // Global malloc() should not be used in this function.
 // Use LowLevelAlloc if required.
-int DeepHeapProfile::FillOrderedProfile(char raw_buffer[], int buffer_size) {
+int DeepHeapProfile::FillOrderedProfile(char raw_buffer[],
+                                        int buffer_size,
+                                        const char* reason) {
   TextBuffer buffer(raw_buffer, buffer_size);
   TextBuffer global_buffer(profiler_buffer_, kProfilerBufferSize);
 
@@ -275,6 +277,12 @@ int DeepHeapProfile::FillOrderedProfile(char raw_buffer[], int buffer_size) {
   buffer.AppendUnsignedLong(time_value, 0);
   buffer.AppendChar('\n');
 
+  if (reason != NULL) {
+    buffer.AppendString("Reason: ", 0);
+    buffer.AppendString(reason, 0);
+    buffer.AppendChar('\n');
+  }
+
   // Fill buffer with the global stats.
   buffer.AppendString(kMMapListHeader, 0);