Add support for --critical-update-version to installer.

chrome/installer/util/installer_state.h

Index: chrome/installer/util/installer_state.h
diff --git a/chrome/installer/util/installer_state.h b/chrome/installer/util/installer_state.h
index 04417be2dcf81bf39428b0b9db33e74b1a6ceb8c..83270a959b2f32438c1a5c838c7ac93761afbc79 100644
--- a/chrome/installer/util/installer_state.h
+++ b/chrome/installer/util/installer_state.h
@@ -14,6 +14,7 @@
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
+#include "base/version.h"
 #include "chrome/installer/util/browser_distribution.h"
 #include "chrome/installer/util/product.h"
 #include "chrome/installer/util/util_constants.h"
@@ -144,6 +145,14 @@ class InstallerState {
   // products are installed.  Ownership is passed to the caller.
   Version* GetCurrentVersion(const InstallationState& machine_state) const;
 
+  // Returns the critical update version if all of the following are true:
+  // - --critical-update-version=CUV was specified on the command-line.
+  // - current_version == NULL or current_version < CUV.

[Finnur, 2011/11/11 10:31:01]

Wait... current_version can be NULL? How come? Is that the 'fresh install' case?

[grt (UTC plus 2), 2011/11/11 11:40:08]

It's a case where the registry data for the current install is missing (due to
the user nuking registry keys, most likely).  

[Finnur, 2011/11/11 12:12:47]

I see.

On 2011/11/11 11:40:08, grt wrote:

+  // - new_version >= CUV.

[Finnur, 2011/11/11 10:31:01]

nit: Maybe use * for bullets instead of - so that "- --critical" doesn't look so
weird? :)

[grt (UTC plus 2), 2011/11/11 11:40:08]

Done.

+  // Otherwise, returns an invalid version.
+  Version DetermineCriticalVersion(const Version* current_version,
+                                   const Version& new_version) const;
+
   // Returns whether or not there is currently a Chrome Frame instance running.
   // Note that there isn't a mechanism to lock Chrome Frame in place, so Chrome
   // Frame may either exit or start up after this is called.
@@ -211,6 +220,7 @@ class InstallerState {
   BrowserDistribution::Type state_type_;
   ScopedVector<Product> products_;
   BrowserDistribution* multi_package_distribution_;
+  Version critical_update_version_;
   Level level_;
   PackageType package_type_;
 #if defined(OS_WIN)