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
+  // (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;
 
   // 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_