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

content/public/browser/plugin_service.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_PUBLIC_BROWSER_PLUGIN_SERVICE_H_
 #define CONTENT_PUBLIC_BROWSER_PLUGIN_SERVICE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 84 matching lines @@
   // Asynchronously loads plugins if necessary and then calls back to the
   // provided function on the calling MessageLoop on completion.
   virtual void GetPlugins(const GetPluginsCallback& callback) = 0;
 
   // Returns information about a pepper plugin if it exists, otherwise NULL.
   // The caller does not own the pointer, and it's not guaranteed to live past
   // the call stack.
   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;
 
   // If the plugin with the given path is running, cleanly shuts it down.
   virtual void ForcePluginShutdown(const base::FilePath& plugin_path) = 0;
 
   // Used to monitor plug-in stability. An unstable plug-in is one that has
   // crashed more than a set number of times in a set time period.
   virtual bool IsPluginUnstable(const base::FilePath& plugin_path) = 0;
 
@@ skipping 42 matching lines @@
   // This can be called from any thread.
   virtual bool GetPluginInfoFromWindow(HWND window,
                                        base::string16* plugin_name,
                                        base::string16* plugin_version) = 0;
 #endif
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_PLUGIN_SERVICE_H_