Provide a counter for thrown JavaScript errors per context

src/counters.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COUNTERS_H_
 #define V8_COUNTERS_H_
 
 #include "include/v8.h"
 #include "src/allocation.h"
 #include "src/base/platform/elapsed-timer.h"
@@ skipping 579 matching lines @@
   SC(total_full_codegen_source_size, V8.TotalFullCodegenSourceSize)   \
   /* Number of contexts created from scratch. */                      \
   SC(contexts_created_from_scratch, V8.ContextsCreatedFromScratch)    \
   /* Number of contexts created by partial snapshot. */               \
   SC(contexts_created_by_snapshot, V8.ContextsCreatedBySnapshot)      \
   /* Number of code objects found from pc. */                         \
   SC(pc_to_code, V8.PcToCode)                                         \
   SC(pc_to_code_cached, V8.PcToCodeCached)                            \
   /* The store-buffer implementation of the write barrier. */         \
   SC(store_buffer_compactions, V8.StoreBufferCompactions)             \
-  SC(store_buffer_overflows, V8.StoreBufferOverflows)
+  SC(store_buffer_overflows, V8.StoreBufferOverflows)                 \
+  /* Number of exceptions thrown */                                   \
+  SC(exceptions_thrown, V8.ExceptionsThrown)
 
 
 #define STATS_COUNTER_LIST_2(SC)                                               \
   /* Number of code stubs. */                                                  \
   SC(code_stubs, V8.CodeStubs)                                                 \
   /* Amount of stub code. */                                                   \
   SC(total_stubs_code_size, V8.TotalStubsCodeSize)                             \
   /* Amount of (JS) compiled code. */                                          \
   SC(total_compiled_code_size, V8.TotalCompiledCodeSize)                       \
   SC(gc_compactor_caused_by_request, V8.GCCompactorCausedByRequest)            \
@@ skipping 275 matching lines @@
 
   explicit Counters(Isolate* isolate);
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(Counters);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COUNTERS_H_