Check whether the Pepper CDM is available before adding the key system.

content/browser/plugin_service_impl.cc

Index: content/browser/plugin_service_impl.cc
diff --git a/content/browser/plugin_service_impl.cc b/content/browser/plugin_service_impl.cc
index 5a79f7dcc845e43f15a74ca7e3b6a4bcd7b0eb06..8ffea2ded4534951164b476e3cce0cd25a44cb86 100644
--- a/content/browser/plugin_service_impl.cc
+++ b/content/browser/plugin_service_impl.cc
@@ -658,7 +658,7 @@ void PluginServiceImpl::RegisterPepperPlugins() {
 PepperPluginInfo* PluginServiceImpl::GetRegisteredPpapiPluginInfo(
     const base::FilePath& plugin_path) {
   PepperPluginInfo* info = NULL;
-  for (size_t i = 0; i < ppapi_plugins_.size(); i++) {
+  for (size_t i = 0; i < ppapi_plugins_.size(); ++i) {
     if (ppapi_plugins_[i].path == plugin_path) {
       info = &ppapi_plugins_[i];
       break;