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

content/public/browser/plugin_service.h

Index: content/public/browser/plugin_service.h
diff --git a/content/public/browser/plugin_service.h b/content/public/browser/plugin_service.h
index 8c28948d21af534755483edb377d70d46ebea467..af8db96a18103a777631a2b61f6dfc1a0131a3e0 100644
--- a/content/public/browser/plugin_service.h
+++ b/content/public/browser/plugin_service.h
@@ -102,6 +102,14 @@ class PluginService {
   virtual PepperPluginInfo* GetRegisteredPpapiPluginInfo(
       const base::FilePath& plugin_path) = 0;
 
+  // Returns whether any Pepper plugin supporting |mime_type| is registered.
+  // Does not determine whether the plugin could actually be instantiated
+  // (i.e. by checking Content Settings).

[scherkus (not reviewing), 2013/09/16 17:42:05]

grammar nit: did you mean to use i.e. ("that is" / "in other words") or e.g.,
("for example")?

the former provides an explicit clarification, the latter provides one of many
possible examples

i.e., if Content Settings isn't the only reason why plugins can't be
instantiated then I'd recommend using e.g., ;)

[ddorwin, 2013/09/16 18:28:58]

Done.

+  // Also does not check whether the plugin can be loaded
+  // (i.e. has all its dependencies).
+  virtual bool IsPepperPluginRegisteredForMimeType(
+      const std::string& mime_type) = 0;
+
   virtual void SetFilter(PluginServiceFilter* filter) = 0;
   virtual PluginServiceFilter* GetFilter() = 0;