Collect array buffer allocation sizes for UMA in megabytes.

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/atomic-utils.h"
@@ skipping 911 matching lines @@
   HR(debug_feature_usage, V8.DebugFeatureUsage, 1, 7, 7)                      \
   HR(incremental_marking_reason, V8.GCIncrementalMarkingReason, 0, 21, 22)    \
   HR(mark_compact_reason, V8.GCMarkCompactReason, 0, 21, 22)                  \
   HR(scavenge_reason, V8.GCScavengeReason, 0, 21, 22)                         \
   HR(young_generation_handling, V8.GCYoungGenerationHandling, 0, 2, 3)        \
   /* Asm/Wasm. */                                                             \
   HR(wasm_functions_per_asm_module, V8.WasmFunctionsPerModule.asm, 1, 100000, \
      51)                                                                      \
   HR(wasm_functions_per_wasm_module, V8.WasmFunctionsPerModule.wasm, 1,       \
      100000, 51)                                                              \
-  HR(array_buffer_big_allocations, V8.ArrayBufferBigAllocations, 1, 32, 32)   \
-  HR(array_buffer_new_size_failures, V8.ArrayBufferNewSizeFailures, 1, 32, 32)
+  HR(array_buffer_big_allocations, V8.ArrayBufferBigAllocations, 0, 4096, 13) \
+  HR(array_buffer_new_size_failures, V8.ArrayBufferNewSizeFailures, 0, 4096, 13)
 
 #define HISTOGRAM_TIMER_LIST(HT)                                               \
   /* Garbage collection timers. */                                             \
   HT(gc_compactor, V8.GCCompactor, 10000, MILLISECOND)                         \
   HT(gc_finalize, V8.GCFinalizeMC, 10000, MILLISECOND)                         \
   HT(gc_finalize_reduce_memory, V8.GCFinalizeMCReduceMemory, 10000,            \
      MILLISECOND)                                                              \
   HT(gc_scavenger, V8.GCScavenger, 10000, MILLISECOND)                         \
   HT(gc_context, V8.GCContext, 10000,                                          \
      MILLISECOND) /* GC context cleanup time */                                \
@@ skipping 394 matching lines @@
 
   explicit Counters(Isolate* isolate);
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(Counters);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COUNTERS_H_