Move new Startup.FirstWebContents.* stats to Startup.FirstWebContents.*2.

components/metrics/proto/profiler_event.proto

 // Copyright 2014 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.
 //
 // Performance metrics collected via Chrome's built-in profiler.
 
 syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
 option java_outer_classname = "ProfilerEventProtos";
@@ skipping 25 matching lines @@
   }
   optional TimeSource time_source = 2;
 
   // An event in the browser life that causes the client-side profiler framework
   // to finish recording of its current instance of ProfilerEventProto, and
   // start recording a new one.
   // It's not guaranteed that the events get triggered in the order they are
   // defined.
   enum ProfilerEvent {
     // The first non-empty paint of the first web contents happened.
-    // Corresponds to the Startup.FirstWebContents.NonEmptyPaint histogram.
+    // Corresponds to the Startup.FirstWebContents.NonEmptyPaint2 histogram.
     EVENT_FIRST_NONEMPTY_PAINT = 0;
   }
 
   // The set of events, in no particular order, that were triggered in the
   // current Chrome session before the recording of this ProfilerEventProto
   // started. It doesn't include the event that triggered the end of this
   // ProfilerEventProto. A given event will not occur twice in this set.
   // The field can be used to find all ProfilerEventProto instances recorded
   // before or not before a given event.
   repeated ProfilerEvent past_session_event = 4;
@@ skipping 60 matching lines @@
       PPAPI_PLUGIN = 12;
       PPAPI_BROKER = 13;
     }
     optional ProcessType process_type = 11;
 
     // The local PID for the process within which this task was executed.
     optional uint32 process_id = 12;
   }
   repeated TrackedObject tracked_object = 3;
 }