Add UMA reports for Linux nacl_helper startup status

content/common/zygote_fork_delegate_linux.h

Index: content/common/zygote_fork_delegate_linux.h
diff --git a/content/common/zygote_fork_delegate_linux.h b/content/common/zygote_fork_delegate_linux.h
index 26dfbc919d1d82111706f336893115db4ec9980e..bae7df2a363f94b2bf06a315183877c068efb113 100644
--- a/content/common/zygote_fork_delegate_linux.h
+++ b/content/common/zygote_fork_delegate_linux.h
@@ -19,9 +19,9 @@
 class ZygoteForkDelegate {
  public:
   // A ZygoteForkDelegate is created during Chrome linux zygote
-  // initialization, and provides "fork()" functionality with
-  // as an alternative to forking the zygote. A new delegate is
-  // passed in as an argument to ZygoteMain().
+  // initialization, and provides "fork()" functionality as an
+  // alternative to forking the zygote.  A new delegate is passed in
+  // as an argument to ZygoteMain().
   ZygoteForkDelegate() {}
   virtual ~ZygoteForkDelegate() {}
 
@@ -31,9 +31,17 @@ class ZygoteForkDelegate {
                     int browserdesc,
                     int sandboxdesc) = 0;
 
-  // Returns 'true' if the delegate would like to handle a given
-  // fork request. Otherwise returns false.
-  virtual bool CanHelp(const std::string& process_type) = 0;
+  // After Init, supply a UMA_HISTOGRAM_ENUMERATION the delegate
+  // would like to supply on the first fork.
+  virtual void InitialUMA(std::string* uma_name,
+                          int* uma_sample,
+                          int* uma_boundary_value) = 0;
+
+  // Returns 'true' if the delegate would like to handle a given fork
+  // request.  Otherwise returns false.  Optionally, fills in uma_name et al
+  // with a report the helper wants to make via UMA_HISTOGRAM_ENUMERATION.
+  virtual bool CanHelp(const std::string& process_type, std::string* uma_name,
+                       int* uma_sample, int* uma_boundary_value) = 0;
 
   // Delegate forks, returning a -1 on failure. Outside the
   // suid sandbox, Fork() returns the Linux process ID. Inside