Report PPAPI plugin load error code to UMA.

chrome/plugin/chrome_content_plugin_client.cc

Index: chrome/plugin/chrome_content_plugin_client.cc
diff --git a/chrome/plugin/chrome_content_plugin_client.cc b/chrome/plugin/chrome_content_plugin_client.cc
index 4e1dee7d4b1e43f2835e6bf5feb0d5e140cb386d..1abe0a3fd905db8aa19a7ab4f259f8f2c64dd706 100644
--- a/chrome/plugin/chrome_content_plugin_client.cc
+++ b/chrome/plugin/chrome_content_plugin_client.cc
@@ -30,9 +30,9 @@ void ChromeContentPluginClient::PreSandboxInitialization() {
   crypto::EnsureNSSInit();
 #elif defined(OS_WIN)
   // crypt32.dll is used to decode X509 certificates for Chromoting.
-  std::string error;
+  base::NativeLibraryLoadError error;
   if (base::LoadNativeLibrary(base::FilePath(L"crypt32.dll"), &error) == NULL)
-    LOG(ERROR) << "Failed to load crypto32.dll: " << error;
+    LOG(ERROR) << "Failed to load crypto32.dll: " << error.ToString();
 #endif // defined(OS_WIN)
 
   // Load media libraries for the Chromoting client plugin.