Add an override flag to enable metrics reporting.

chrome/common/chrome_switches.cc

 // 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.
 
 #include "chrome/common/chrome_switches.h"
 
 #include "base/base_switches.h"
 #include "base/command_line.h"
 #include "build/build_config.h"
 #include "ppapi/features/features.h"
@@ skipping 338 matching lines @@
 // running a tab's onunload js handler independently of the GUI -
 // crbug.com/142458 .
 const char kEnableFastUnload[] = "enable-fast-unload";
 
 // Enables the Material Design feedback form.
 const char kEnableMaterialDesignFeedback[] = "enable-md-feedback";
 
 // Enables the Material Design policy page at chrome://md-policy.
 const char kEnableMaterialDesignPolicyPage[]  = "enable-md-policy-page";
 
+// Forces metrics reporting to be enabled and may tag logs as examples.

[Alexei Svitkine (slow), 2017/05/04 21:36:01]

Nit: Omit the "and may tag logs as examples" part. It can be re-added if we ever
implement something like that.

[Steven Holte, 2017/05/04 22:07:04]

Done.

+const char kEnableMetricsReportingForTesting[] =
+    "enable-metrics-reporting-for-testing";
+
 // Runs the Native Client inside the renderer process and enables GPU plugin
 // (internally adds lEnableGpuPlugin to the command line).
 const char kEnableNaCl[]                    = "enable-nacl";
 
 // Enables tracing for each navigation. It will attempt to trace each navigation
 // for 10s, until the buffer is full, or until the next navigation.
 // It only works if a URL was provided by --trace-upload-url.
 const char kEnableNavigationTracing[] = "enable-navigation-tracing";
 
 // Enables the network-related benchmarking extensions.
@@ skipping 807 matching lines @@
 
 // -----------------------------------------------------------------------------
 // DO NOT ADD YOUR VERY NICE FLAGS TO THE BOTTOM OF THIS FILE.
 //
 // You were going to just dump your switches here, weren't you? Instead, please
 // put them in alphabetical order above, or in order inside the appropriate
 // ifdef at the bottom. The order should match the header.
 // -----------------------------------------------------------------------------
 
 }  // namespace switches