Use the WebKit default fonts when specifying generic font families.

ppapi/proxy/plugin_dispatcher.h

Index: ppapi/proxy/plugin_dispatcher.h
===================================================================
--- ppapi/proxy/plugin_dispatcher.h	(revision 86427)
+++ ppapi/proxy/plugin_dispatcher.h	(working copy)
@@ -15,6 +15,7 @@
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/proxy/dispatcher.h"
 #include "ppapi/shared_impl/function_group_base.h"
+#include "ppapi/shared_impl/ppapi_preferences.h"
 
 class MessageLoop;
 
@@ -22,6 +23,10 @@
 class WaitableEvent;
 }
 
+namespace ppapi {
+struct Preferences;
+}
+
 namespace pp {
 namespace proxy {
 
@@ -108,6 +113,9 @@
   // Returns the WebKitForwarding object used to forward events to WebKit.
   ppapi::WebKitForwarding* GetWebKitForwarding();
 
+  // Returns the Preferences.
+  const ppapi::Preferences& preferences() const { return preferences_; }
+
   // Returns the "new-style" function API for the given interface ID, creating
   // it if necessary.
   // TODO(brettw) this is in progress. It should be merged with the target
@@ -124,6 +132,7 @@
 
   // IPC message handlers.
   void OnMsgSupportsInterface(const std::string& interface_name, bool* result);
+  void OnMsgSetPreferences(const ::ppapi::Preferences& prefs);
 
   PluginDelegate* plugin_delegate_;
 
@@ -140,6 +149,8 @@
   typedef base::hash_map<PP_Instance, InstanceData> InstanceDataMap;
   InstanceDataMap instance_map_;
 
+  ppapi::Preferences preferences_;
+
   DISALLOW_COPY_AND_ASSIGN(PluginDispatcher);
 };