DO NOT SUBMIT: add main dex list check to classloader.

base/BUILD.gn

Index: base/BUILD.gn
diff --git a/base/BUILD.gn b/base/BUILD.gn
index aa1225f43ceb2d12c672037f715dfd81f584a4bd..91539ca15e616133381bdfa95150c5b24eb3f6ea 100644
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -2505,6 +2505,7 @@ if (is_android) {
       "android/java/src/org/chromium/base/PerfTraceEvent.java",
       "android/java/src/org/chromium/base/PowerMonitor.java",
       "android/java/src/org/chromium/base/Promise.java",
+      "android/java/src/org/chromium/base/Reflect.java",
       "android/java/src/org/chromium/base/ResourceExtractor.java",
       "android/java/src/org/chromium/base/SecureRandomInitializer.java",
       "android/java/src/org/chromium/base/StreamUtil.java",
@@ -2538,6 +2539,7 @@ if (is_android) {
       "android/java/src/org/chromium/base/metrics/RecordHistogram.java",
       "android/java/src/org/chromium/base/metrics/RecordUserAction.java",
       "android/java/src/org/chromium/base/metrics/StatisticsRecorderAndroid.java",
+      "android/java/src/org/chromium/base/multidex/ChromiumClassLoader.java",
       "android/java/src/org/chromium/base/multidex/ChromiumMultiDexInstaller.java",
       "android/java/src/org/chromium/base/process_launcher/ChildProcessCreationParams.java",
       "android/java/src/org/chromium/base/process_launcher/FileDescriptorInfo.java",