Collect information about failing histogram factory calls.

base/metrics/persistent_histogram_allocator.cc

Index: base/metrics/persistent_histogram_allocator.cc
diff --git a/base/metrics/persistent_histogram_allocator.cc b/base/metrics/persistent_histogram_allocator.cc
index 6006d31fbee70031acb901fb6a0f04a944f5ff04..0eab0163fcf0be0889c85b805cef64b0d0099c64 100644
--- a/base/metrics/persistent_histogram_allocator.cc
+++ b/base/metrics/persistent_histogram_allocator.cc
@@ -295,6 +295,12 @@ scoped_ptr<HistogramBase> PersistentHistogramAllocator::CreateHistogram(
   // validated below; the local copy is to ensure that the contents cannot
   // be externally changed between validation and use.
   PersistentHistogramData histogram_data = *histogram_data_ptr;
+  CHECK_EQ(histogram_data.histogram_type, histogram_data_ptr->histogram_type);
+  CHECK_EQ(histogram_data.flags, histogram_data_ptr->flags);
+  CHECK_EQ(histogram_data.minimum, histogram_data_ptr->minimum);
+  CHECK_EQ(histogram_data.maximum, histogram_data_ptr->maximum);
+  CHECK_EQ(histogram_data.bucket_count, histogram_data_ptr->bucket_count);
+  CHECK_EQ(histogram_data.ranges_checksum, histogram_data_ptr->ranges_checksum);
 
   HistogramBase::Sample* ranges_data =
       memory_allocator_->GetAsObject<HistogramBase::Sample>(
@@ -345,6 +351,8 @@ scoped_ptr<HistogramBase> PersistentHistogramAllocator::CreateHistogram(
   HistogramBase::AtomicCount* logged_data =
       counts_data + histogram_data.bucket_count;
 
+  CHECK_LT(0, histogram_data.minimum);
+  CHECK_LT(0, histogram_data.maximum);
   std::string name(histogram_data_ptr->name);
   scoped_ptr<HistogramBase> histogram;
   switch (histogram_data.histogram_type) {