Introduce --cancel-first-run and reduce the strength of --no-first-run.

chrome/browser/first_run/first_run.h

Index: chrome/browser/first_run/first_run.h
diff --git a/chrome/browser/first_run/first_run.h b/chrome/browser/first_run/first_run.h
index 9f86f830437330ed6c3fce68cbe1b26c59e38037..b180e29fc3fa903e4576c015afa4f0b2dee304ad 100644
--- a/chrome/browser/first_run/first_run.h
+++ b/chrome/browser/first_run/first_run.h
@@ -10,6 +10,7 @@
 
 #include "base/basictypes.h"
 
+class CommandLine;
 class GURL;
 class Profile;
 
@@ -84,6 +85,10 @@ struct MasterPrefs {
 // Returns true if this is the first time chrome is run for this user.
 bool IsChromeFirstRun();
 
+// Returns true if |command_line|'s switches explicitly specify that first run
+// should be suppressed in the current run.
+bool IsFirstRunSuppressed(const CommandLine& command_line);
+
 // Creates the first run sentinel if needed. This should only be called after
 // the process singleton has been grabbed by the current process
 // (http://crbug.com/264694).