Disable getting histogram data from child processes.

base/metrics/histogram_snapshot_manager.cc

 // Copyright (c) 2012 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 "base/metrics/histogram_snapshot_manager.h"
 
+#include "base/compiler_specific.h"
+#include "base/debug/alias.h"
 #include "base/metrics/statistics_recorder.h"
+#include "base/string_util.h"
 
 using base::Histogram;
 using base::StatisticsRecorder;
 
 namespace base {
 
 HistogramSnapshotManager::HistogramSnapshotManager(
     HistogramFlattener* histogram_flattener)
     : histogram_flattener_(histogram_flattener) {
   DCHECK(histogram_flattener_);
@@ skipping 19 matching lines @@
 void HistogramSnapshotManager::PrepareDelta(const Histogram& histogram) {
   DCHECK(histogram_flattener_);
 
   // Get up-to-date snapshot of sample stats.
   Histogram::SampleSet snapshot;
   histogram.SnapshotSample(&snapshot);
   const std::string& histogram_name = histogram.histogram_name();
 
   int corruption = histogram.FindCorruption(snapshot);
 
+  char histogram_name_buf[128];
+  base::strlcpy(histogram_name_buf,
+                histogram_name.c_str(),
+                arraysize(histogram_name_buf));
+  base::debug::Alias(histogram_name_buf);
+
   // Crash if we detect that our histograms have been overwritten.  This may be
   // a fair distance from the memory smasher, but we hope to correlate these
   // crashes with other events, such as plugins, or usage patterns, etc.
   if (Histogram::BUCKET_ORDER_ERROR & corruption) {
     // The checksum should have caught this, so crash separately if it didn't.
     CHECK_NE(0, Histogram::RANGE_CHECKSUM_ERROR & corruption);
     CHECK(false);  // Crash for the bucket order corruption.
   }
   // Checksum corruption might not have caused order corruption.
   CHECK_EQ(0, Histogram::RANGE_CHECKSUM_ERROR & corruption);
@@ skipping 41 matching lines @@
   }
 
   // Snapshot now contains only a delta to what we've already_logged.
   if (snapshot.redundant_count() > 0) {
     histogram_flattener_->RecordDelta(histogram, snapshot);
     // Add new data into our running total.
     already_logged->Add(snapshot);
   }
 }
 }  // namespace base