Return a NULL histogram pointer on construction error

base/metrics/histogram.cc

Index: base/metrics/histogram.cc
diff --git a/base/metrics/histogram.cc b/base/metrics/histogram.cc
index fbe66d05d29fd3c2896f8499dd1dc07d9793d095..2ae444e3c9f4f86b2f94063da22418402a02da14 100644
--- a/base/metrics/histogram.cc
+++ b/base/metrics/histogram.cc
@@ -110,7 +110,16 @@ HistogramBase* Histogram::FactoryGet(const string& name,
   }
 
   DCHECK_EQ(HISTOGRAM, histogram->GetHistogramType());
-  CHECK(histogram->HasConstructionArguments(minimum, maximum, bucket_count));
+  if (!histogram->HasConstructionArguments(minimum, maximum, bucket_count)) {
+    // The construction arguments do not match the existing histogram.  This can
+    // come about if an extension updates in the middle of a chrome run and has
+    // changed one of them.  We return a dummy object here instead of crashing
+    // so poor use of extension/Pepper APIs do not cause crashes in Chrome.
+    DLOG(ERROR) << "Histogram " << name << " has bad construction arguments";
+    DummyHistogram* tentative_histogram = new DummyHistogram;
+    histogram =
+        StatisticsRecorder::RegisterOrDeleteDuplicate(tentative_histogram);
+  }
   return histogram;
 }
 
@@ -567,7 +576,16 @@ HistogramBase* LinearHistogram::FactoryGetWithRangeDescription(
   }
 
   DCHECK_EQ(LINEAR_HISTOGRAM, histogram->GetHistogramType());
-  CHECK(histogram->HasConstructionArguments(minimum, maximum, bucket_count));
+  if (!histogram->HasConstructionArguments(minimum, maximum, bucket_count)) {
+    // The construction arguments do not match the existing histogram.  This can
+    // come about if an extension updates in the middle of a chrome run and has
+    // changed one of them.  We return a dummy object here instead of crashing
+    // so poor use of extension/Pepper APIs do not cause crashes in Chrome.
+    DLOG(ERROR) << "Histogram " << name << " has bad construction arguments";
+    DummyHistogram* tentative_histogram = new DummyHistogram;
+    histogram =
+        StatisticsRecorder::RegisterOrDeleteDuplicate(tentative_histogram);
+  }
   return histogram;
 }
 
@@ -831,4 +849,10 @@ BucketRanges* CustomHistogram::CreateBucketRangesFromCustomRanges(
   return bucket_ranges;
 }
 
+bool DummyHistogram::AddSamplesFromPickle(PickleIterator* iter) {
+  return false;
+}
+
+DummyHistogram::DummyHistogram() : Histogram("Dummy", 0, 1, NULL) {}
+
 }  // namespace base