Merge subprocess metrics into global StatisticsRecorder.

base/metrics/histogram.cc

Index: base/metrics/histogram.cc
diff --git a/base/metrics/histogram.cc b/base/metrics/histogram.cc
index 3571657513f6482c5724f721c17e8a2c354ab79a..aa042106dcb9bb74fae3a767e734cfc31e5209b8 100644
--- a/base/metrics/histogram.cc
+++ b/base/metrics/histogram.cc
@@ -64,8 +64,7 @@ bool ReadHistogramArguments(PickleIterator* iter,
   }
 
   // We use the arguments to find or create the local version of the histogram
-  // in this process, so we need to clear the IPC flag.
-  DCHECK(*flags & HistogramBase::kIPCSerializationSourceFlag);
+  // in this process, so we need to clear any IPC flag.
   *flags &= ~HistogramBase::kIPCSerializationSourceFlag;
 
   return true;