Add weekly crash counters, refactor metrics_daemon, respect opt-in in library.

c_metrics_library.h

Index: c_metrics_library.h
diff --git a/c_metrics_library.h b/c_metrics_library.h
index 6d1e6f907f7f41a8c6de6200a612151d1a152896..e691ad66ef7c4bfe7c962785ec241593d02d65fc 100644
--- a/c_metrics_library.h
+++ b/c_metrics_library.h
@@ -21,13 +21,17 @@ void CMetricsLibraryInit(CMetricsLibrary handle);
 
 // C wrapper for MetricsLibrary::SendToUMA.
 int CMetricsLibrarySendToUMA(CMetricsLibrary handle,
-			     const char* name, int sample,
-			     int min, int max, int nbuckets);
+                             const char* name, int sample,
+                             int min, int max, int nbuckets);
 
 // C wrapper for MetricsLibrary::SendEnumToUMA.
 int CMetricsLibrarySendEnumToUMA(CMetricsLibrary handle,
-				 const char* name, int sample, int max);
+                                 const char* name, int sample, int max);
+
+// C wrapper for MetricsLibrary::AreMetricsEnabled.
+int CMetricsLibraryAreMetricsEnabled(CMetricsLibrary handle);
+
 #if defined(__cplusplus)
 }
 #endif
-#endif	// C_METRICS_LIBRARY_H_
+#endif  // C_METRICS_LIBRARY_H_