[chromecast] ExternalMetrics has to destroy itself in file thread.

chromecast/browser/metrics/external_metrics.cc

Index: chromecast/browser/metrics/external_metrics.cc
diff --git a/chromecast/browser/metrics/external_metrics.cc b/chromecast/browser/metrics/external_metrics.cc
index ce9884cb37dba966e1fae70867ac48ae3181d9a0..4b5f5d92f9713617a5adef2fc2cfcec71286d41c 100644
--- a/chromecast/browser/metrics/external_metrics.cc
+++ b/chromecast/browser/metrics/external_metrics.cc
@@ -58,7 +58,19 @@ ExternalMetrics::ExternalMetrics(
   DCHECK(stability_provider);
 }
 
-ExternalMetrics::~ExternalMetrics() {}
+ExternalMetrics::~ExternalMetrics() {
+}
+
+void ExternalMetrics::DestroySelf() {
+  if (!content::BrowserThread::CurrentlyOn(content::BrowserThread::FILE)) {

[gunsch, 2015/01/09 18:56:19]

Why does it need to be destroyed on the file thread? Is it because of the weak
pointer factory?

[gfhuang, 2015/01/09 19:10:45]

Yes

+    content::BrowserThread::PostTask(
+        content::BrowserThread::FILE,
+        FROM_HERE,
+        base::Bind(&ExternalMetrics::DestroySelf, base::Unretained(this)));
+    return;
+  }
+  delete this;
+}
 
 void ExternalMetrics::Start() {
   ScheduleCollector();