Add truncate and cancel for FileWriter; write and tests will come in later CL...

webkit/glue/plugins/pepper_file_system.cc

Index: webkit/glue/plugins/pepper_file_system.cc
===================================================================
--- webkit/glue/plugins/pepper_file_system.cc	(revision 61078)
+++ webkit/glue/plugins/pepper_file_system.cc	(working copy)
@@ -54,6 +54,10 @@
     RunCallback(error_code);
   }
 
+  virtual void DidWrite(int64 bytes, bool complete) {
+    NOTREACHED();
+  }
+
  private:
   void RunCallback(base::PlatformFileError error_code) {
     if (!module_.get() || !callback_.func)
@@ -105,6 +109,10 @@
     RunCallback(error_code, base::PlatformFileInfo());
   }
 
+  virtual void DidWrite(int64 bytes, bool complete) {
+    NOTREACHED();
+  }
+
  private:
   void RunCallback(base::PlatformFileError error_code,
                    const base::PlatformFileInfo& file_info) {