mediaresourcemanager: change resource manager service log to use ring buffer.

move the ring buffer implementation from libcameraservice to media include.

also add line prefix support to the service log.

Bug: 20637674
Change-Id: Ib6b32f31abe92c42644ef7012f1e3d46220ccfbd
diff --git a/services/mediaresourcemanager/ResourceManagerService.cpp b/services/mediaresourcemanager/ResourceManagerService.cpp
index 3c093f9..e2b6695 100644
--- a/services/mediaresourcemanager/ResourceManagerService.cpp
+++ b/services/mediaresourcemanager/ResourceManagerService.cpp
@@ -126,8 +126,8 @@
             }
         }
     }
-    result.append("  Logs:\n");
-    result.append(mServiceLog->toString());
+    result.append("  Events logs (most recent at top):\n");
+    result.append(mServiceLog->toString("    " /* linePrefix */));
 
     write(fd, result.string(), result.size());
     return OK;