Update to Chromium revision ad51088c (#444943)

libcef/common/crash_reporting_win.h

@@ -8,4 +8,8 @@ namespace crash_reporting_win {
 // state from chrome_elf via exported functions.
 bool InitializeCrashReportingForModule();
 
+// Called from libcef early in main process startup to ensure that the crash
+// handler process is started before other sub-processes are created.
+void BlockUntilHandlerStarted();
+
 }  // namespace crash_reporting_win