Report PPAPI plugin load error code to UMA.

content/ppapi_plugin/ppapi_thread.cc

Index: content/ppapi_plugin/ppapi_thread.cc
diff --git a/content/ppapi_plugin/ppapi_thread.cc b/content/ppapi_plugin/ppapi_thread.cc
index ea7431378aa124a1247a55ab2f098f31cbb209c3..023f045e29f3e73e0a51d90539b8bcb99fb08a08 100644
--- a/content/ppapi_plugin/ppapi_thread.cc
+++ b/content/ppapi_plugin/ppapi_thread.cc
@@ -269,12 +269,16 @@ void PpapiThread::OnLoadPlugin(const base::FilePath& path,
   base::ScopedNativeLibrary library;
   if (plugin_entry_points_.initialize_module == NULL) {
     // Load the plugin from the specified library.
-    std::string error;
-    library.Reset(base::LoadNativeLibrary(path, &error));
+    std::string error_message;
+    uint32 error_code = 0;
+    library.Reset(base::LoadNativeLibrary(path, &error_message, &error_code));
     if (!library.is_valid()) {
       LOG(ERROR) << "Failed to load Pepper module from "
-        << path.value() << " (error: " << error << ")";
+        << path.value() << " (error: " << error_message << " with error code "

[ddorwin, 2014/03/20 22:01:12]

nit: You could also do something like "error 'code' - 'message'"

[xhwang, 2014/03/21 01:42:58]

Done.

+        << error_code << ")";
       ReportLoadResult(path, LOAD_FAILED);
+      // Report detailed reason for load failure.
+      ReportLoadErrorCode(path, error_code);
       return;
     }
 
@@ -519,4 +523,25 @@ void PpapiThread::ReportLoadResult(const base::FilePath& path,
   histogram->Add(result);
 }
 
+void PpapiThread::ReportLoadErrorCode(const base::FilePath& path,
+                                      uint32 error_code) {
+  // See http://msdn.microsoft.com/en-us/library/ms681381.aspx

[ddorwin, 2014/03/20 22:01:12]

This is based on only Win reporting an error code. That should probably be
mentioned, along with some type of DCHECK that error_code < kMaxLoadErrorCode or
error_code==0 if not OS_WIN.

[xhwang, 2014/03/21 01:42:58]

Not required since we use sparse histogram.

+  static const uint32 kMaxLoadErrorCode = 16000;
+
+  std::ostringstream histogram_name;
+  histogram_name << "Plugin.Ppapi" << (is_broker_ ? "Broker" : "Plugin")
+                 << "LoadErrorCode_" << path.BaseName().MaybeAsASCII();
+
+  // Note: This leaks memory, which is expected behavior.
+  base::HistogramBase* histogram =
+      base::LinearHistogram::FactoryGet(

[ddorwin, 2014/03/20 22:01:12]

Should this be sparse?

[xhwang, 2014/03/21 01:42:58]

Good point. Done.

+          histogram_name.str(),
+          1,
+          kMaxLoadErrorCode,
+          kMaxLoadErrorCode + 1,
+          base::HistogramBase::kUmaTargetedHistogramFlag);
+
+  histogram->Add(error_code);
+}
+
 }  // namespace content