Inform GetEntropySource of whether or not metrics reporting will be enabled.

chrome/common/chrome_switches.cc

Index: chrome/common/chrome_switches.cc
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index 43af00e6418587d181f4af446c96c317f31eff03..536c0323632cfdd7cae67079c54e28062f52b0bb 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -573,6 +573,12 @@ const char kEnableMediaGalleryUI[]          = "enable-media-gallery-ui";
 // Allows reporting memory info (JS heap size) to page.
 const char kEnableMemoryInfo[]              = "enable-memory-info";
 
+// Enables metrics recording and reporting in the browser startup sequence, as
+// if this was an official Chrome build where the user allowed metrics
+// reporting. This is used for testing only.
+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";