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..213fc5bd67fd500f5738a2a81cdbca80c44a2b86 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
+  // (e.g. by checking Content Settings).

[Bernhard Bauer, 2013/09/16 19:16:03]

Not sure whether we want to mention content settings here at all, as that's not
a content thing. Maybe just mention that the embedder has the last word whether
a plugin will actually be loaded?

[ddorwin, 2013/09/16 21:44:51]

Done. I changed it to two generic examples. I think these examples are useful to
understanding how it should work.

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