GWP-ASan: Report histogram on GWP-ASan crash

In https://cr-rev.appspot.com/c/1594825 I refactored histogram reporting
and accidentally changed it to only report error values and never report
that a GWP-ASan crash was seen. Fix that.

Bug: 956824
Change-Id: I4a1a55fe45db380fc5a00952f304212698c37994
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1632896
Auto-Submit: Vlad Tsyrklevich <vtsyrklevich@chromium.org>
Commit-Queue: Vitaly Buka <vitalybuka@chromium.org>
Reviewed-by: Vitaly Buka <vitalybuka@chromium.org>
Cr-Commit-Position: refs/heads/master@{#663906}

components/gwp_asan/crash_handler/crash_analyzer.cc

@@ -255,6 +255,7 @@ bool CrashAnalyzer::AnalyzeCrashedAllocator(
                          metadata.dealloc, proto->mutable_deallocation());
   }
 
+  ReportHistogram(allocator, GwpAsanCrashAnalysisResult::kGwpAsanCrash);
   return true;
 }
 

components/gwp_asan/crash_handler/crash_analyzer_unittest.cc

@@ -100,7 +100,9 @@ TEST_F(CrashAnalyzerTest, StackTraceCollection) {
       CrashAnalyzer::GetExceptionInfo(process_snapshot_, &proto);
   ASSERT_TRUE(proto_present);
 
-  histogram_tester.ExpectTotalCount(kMallocHistogramName, 0);
+  int result = static_cast<int>(GwpAsanCrashAnalysisResult::kGwpAsanCrash);
+  EXPECT_THAT(histogram_tester.GetAllSamples(kMallocHistogramName),
+              testing::ElementsAre(base::Bucket(result, 1)));
   histogram_tester.ExpectTotalCount(kPartitionAllocHistogramName, 0);
 
   ASSERT_TRUE(proto.has_allocation());