Add a switch to emit browser histograms.

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 6b364cf2b9a33616009d9f222d62f05b56b2b62f..ffcd9208466e256147f10bc617e7a2196f6d8097 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -520,6 +520,10 @@ const char kDnsLogDetails[]                 = "dns-log-details";
 // Disables prefetching of DNS information.
 const char kDnsPrefetchDisable[]            = "dns-prefetch-disable";
 
+// Requests that a running browser process dump its collected histograms to a
+// given file.
+const char kDumpBrowserHistograms[]         = "dump-browser-histograms";
+
 // If set, Flash fullscreen widgets are embedded within the browser window and
 // with the same UX as HTML5 fullscreen.
 //