[libfuzzer] force use_prebuilt_instrumented_libraries for libfuzzer

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 b7053e733ede5b5bd0677009d2a0543f63a8c201..d964493e94f4ccb7a3b949d6f0d7144acbac2cde 100644
--- a/build/config/sanitizers/sanitizers.gni
+++ b/build/config/sanitizers/sanitizers.gni
@@ -155,10 +155,15 @@ assert(!using_sanitizer || is_clang,
 prebuilt_instrumented_libraries_available =
     is_msan && (msan_track_origins == 0 || msan_track_origins == 2)
 
-if (use_libfuzzer && is_asan && is_linux) {
-  # We do leak checking with libFuzzer on Linux. Set is_lsan for code that
-  # relies on LEAK_SANITIZER define to avoid false positives.
-  is_lsan = true
+if (use_libfuzzer && is_linux) {
+  if (is_asan) {
+    # We do leak checking with libFuzzer on Linux. Set is_lsan for code that
+    # relies on LEAK_SANITIZER define to avoid false positives.
+    is_lsan = true
+  }
+  if (is_msan) {
+    use_prebuilt_instrumented_libraries = true
+  }
 }
 
 # MSan only links Chrome properly in release builds (brettw -- 9/1/2015). The