[microdump] Move microdump writes to the crash ring-buffer log

src/client/linux/log/log.h

 // Copyright (c) 2012, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
@@ skipping 18 matching lines @@
 
 #ifndef CLIENT_LINUX_LOG_LOG_H_
 #define CLIENT_LINUX_LOG_LOG_H_
 
 #include <stddef.h>
 
 namespace logger {
 
 int write(const char* buf, size_t nbytes);
 
+// In the case of Android the log can be written to the default system log
+// (default behavior of write() above, or to the crash log (see
+// writeToCrashLog() below).
+#if defined(__ANDROID__)
+
+// The logger must be initialized in a non-compromised context.
+void initializeCrashLogWriter();
+
+// Once initialized, writeToCrashLog is safe to use in a compromised context,
+// even if the initialization failed, in which case this will silently fall
+// back on write().
+int writeToCrashLog(const char* buf);
+#endif
+
 }  // namespace logger
 
 #endif  // CLIENT_LINUX_LOG_LOG_H_