Allow null exception reporter. am: 8590c7925f am: 71a2fd0f21 am: 8137343387

Original change: https://android-review.googlesource.com/c/platform/external/libchrome/+/1454675

Change-Id: I91a1bfa4a00e9b811015324b78899974d69fa824
diff --git a/base/android/java_exception_reporter.cc b/base/android/java_exception_reporter.cc
index 96eb38e..be3e703 100644
--- a/base/android/java_exception_reporter.cc
+++ b/base/android/java_exception_reporter.cc
@@ -38,8 +38,11 @@
 }
 
 void SetJavaException(const char* exception) {
-  DCHECK(g_java_exception_callback);
-  g_java_exception_callback(exception);
+  // No need to print exception because they are already logged via
+  // env->ExceptionDescribe() within jni_android.cc.
+  if (g_java_exception_callback) {
+    g_java_exception_callback(exception);
+  }
 }
 
 void JNI_JavaExceptionReporter_ReportJavaException(