crash-reporter: Capture and send recent update_engine logs when it crashes

crash_collector.h

Index: crash_collector.h
diff --git a/crash_collector.h b/crash_collector.h
index 219c8af6ec85d2d03937dd0779db081faaa3cac8..772de24b7d016d08efa3e53bd3bb41dcd1601089 100644
--- a/crash_collector.h
+++ b/crash_collector.h
@@ -39,9 +39,11 @@ class CrashCollector {
   FRIEND_TEST(CrashCollectorTest, CheckHasCapacityUsual);
   FRIEND_TEST(CrashCollectorTest, GetCrashDirectoryInfo);
   FRIEND_TEST(CrashCollectorTest, GetCrashPath);
+  FRIEND_TEST(CrashCollectorTest, GetLogContents);
   FRIEND_TEST(CrashCollectorTest, ForkExecAndPipe);
   FRIEND_TEST(CrashCollectorTest, FormatDumpBasename);
   FRIEND_TEST(CrashCollectorTest, Initialize);
+  FRIEND_TEST(CrashCollectorTest, IsCommentLine);
   FRIEND_TEST(CrashCollectorTest, MetaData);
   FRIEND_TEST(CrashCollectorTest, ReadKeyValueFile);
   FRIEND_TEST(CrashCollectorTest, Sanitize);
@@ -102,12 +104,21 @@ class CrashCollector {
   // crash.
   bool CheckHasCapacity(const FilePath &crash_directory);
 
+  // Checks if the line starts with '#' after optional whitespace.
+  static bool IsCommentLine(const std::string &line);
+
   // Read the given file of form [<key><separator><value>\n...] and return
   // a map of its contents.
   bool ReadKeyValueFile(const FilePath &file,
                         char separator,
                         std::map<std::string, std::string> *dictionary);
 
+  // Write a log applicable to |exec_name| to |output_file| based on the
+  // log configuration file at |config_path|.
+  bool GetLogContents(const FilePath &config_path,
+                      const std::string &exec_name,
+                      const FilePath &output_file);
+
   // Add non-standard meta data to the crash metadata file.  Call
   // before calling WriteCrashMetaData.  Key must not contain "=" or
   // "\n" characters.  Value must not contain "\n" characters.