Make heap snapshot string limit configurable.

R=ulan@chromium.org

Bug: v8:7402
Change-Id: Ia9d79723ebf63d30528b0d8e639555d08be38531
Reviewed-on: https://chromium-review.googlesource.com/899063Reviewed-by: Alexei Filippov <alph@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51226}

src/flag-definitions.h

@@ -917,6 +917,8 @@ DEFINE_BOOL(heap_profiler_trace_objects, false,
             "Dump heap object allocations/movements/size_updates")
 DEFINE_BOOL(heap_profiler_use_embedder_graph, true,
             "Use the new EmbedderGraph API to get embedder nodes")
+DEFINE_INT(heap_snapshot_string_limit, 1024,
+           "truncate strings to this length in the heap snapshot")
 
 // sampling-heap-profiler.cc
 DEFINE_BOOL(sampling_heap_profiler_suppress_randomness, false,

src/profiler/strings-storage.cc

@@ -80,7 +80,7 @@ const char* StringsStorage::GetVFormatted(const char* format, va_list args) {
 const char* StringsStorage::GetName(Name* name) {
   if (name->IsString()) {
     String* str = String::cast(name);
-    int length = Min(kMaxNameSize, str->length());
+    int length = Min(FLAG_heap_snapshot_string_limit, str->length());
     int actual_length = 0;
     std::unique_ptr<char[]> data = str->ToCString(
         DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL, 0, length, &actual_length);

src/profiler/strings-storage.h

@@ -31,8 +31,6 @@ class StringsStorage {
   const char* GetFunctionName(const char* name);
 
  private:
-  static const int kMaxNameSize = 1024;
-
   static bool StringsMatch(void* key1, void* key2);
   const char* AddOrDisposeString(char* str, int len);
   base::CustomMatcherHashMap::Entry* GetEntry(const char* str, int len);