Bug 1070755: Add telemetry for timing PluginAsyncSurrogate::WaitForInit; r=vladan

dom/plugins/ipc/PluginAsyncSurrogate.cpp

@@ -12,6 +12,7 @@
 #include "mozilla/plugins/PluginInstanceParent.h"
 #include "mozilla/plugins/PluginModuleParent.h"
 #include "mozilla/plugins/PluginScriptableObjectParent.h"
+#include "mozilla/Telemetry.h"
 #include "nsJSNPRuntime.h"
 #include "nsNPAPIPlugin.h"
 #include "nsNPAPIPluginInstance.h"
@@ -410,6 +411,8 @@ PluginAsyncSurrogate::WaitForInit()
   if (mAcceptCalls) {
     return true;
   }
+  Telemetry::AutoTimer<Telemetry::BLOCKED_ON_PLUGINASYNCSURROGATE_WAITFORINIT_MS>
+    timer(mParent->GetHistogramKey());
   bool result = false;
   MOZ_ASSERT(mParent);
   if (mParent->IsChrome()) {

toolkit/components/telemetry/Histograms.json

@@ -7029,6 +7029,15 @@
     "keyed": true,
     "description": "Time (ms) that the main thread has been blocked on NPP_NewStream in an IPC plugin"
   },
+  "BLOCKED_ON_PLUGINASYNCSURROGATE_WAITFORINIT_MS": {
+    "expires_in_version": "40",
+    "kind": "exponential",
+    "high": "10000",
+    "n_buckets": 20,
+    "extended_statistics_ok": true,
+    "keyed": true,
+    "description": "Time (ms) that the main thread has been blocked on PluginAsyncSurrogate::WaitForInit in an IPC plugin"
+  },
   "BLOCKED_ON_PLUGIN_INSTANCE_DESTROY_MS": {
     "expires_in_version": "40",
     "kind": "exponential",