Use new sanitizer coverage flags.

build/config/sanitizers/sanitizers.gni

Index: build/config/sanitizers/sanitizers.gni
diff --git a/build/config/sanitizers/sanitizers.gni b/build/config/sanitizers/sanitizers.gni
index 585a0658d695fdca31f0e625fc2b9b0f69a7c188..17f4d9633f0e141f84c0dfe130de02982e79dead 100644
--- a/build/config/sanitizers/sanitizers.gni
+++ b/build/config/sanitizers/sanitizers.gni
@@ -92,10 +92,10 @@ declare_args() {
 
   # Value for -fsanitize-coverage flag. Setting this causes
   # use_sanitizer_coverage to be enabled.
-  # Default value when unset and use_afl=true:
-  # trace-pc
+  # Default value when unset and use_afl=true or use_libfuzzer=true:
+  #     trace-pc-guard
   # Default value when unset and use_sanitizer_coverage=true:
-  #     edge,indirect-calls,8bit-counters
+  #     trace-pc-guard,indirect-calls
   sanitizer_coverage_flags = ""
 
   # Keep symbol level when building with sanitizers. When sanitizers are
@@ -154,7 +154,7 @@ declare_args() {
 if ((use_afl || use_libfuzzer) && sanitizer_coverage_flags == "") {
   sanitizer_coverage_flags = "trace-pc-guard"
 } else if (use_sanitizer_coverage && sanitizer_coverage_flags == "") {
-  sanitizer_coverage_flags = "edge,indirect-calls,8bit-counters"
+  sanitizer_coverage_flags = "trace-pc-guard,indirect-calls"
 }
 
 using_sanitizer =