Move "default for protocol" probing logic out of shell_integration_win.cc into shell_util.cc.

chrome/installer/util/shell_util.h

Index: chrome/installer/util/shell_util.h
diff --git a/chrome/installer/util/shell_util.h b/chrome/installer/util/shell_util.h
index a67a7243fb62c2564f76b264a5f2edc65a6a1431..50c49e1e80a8456c44d55268031c6f369e394acb 100644
--- a/chrome/installer/util/shell_util.h
+++ b/chrome/installer/util/shell_util.h
@@ -32,6 +32,13 @@ class ShellUtil {
     SYSTEM_LEVEL = 0x2   // Make any shell changes only at the system level
   };
 
+  // Chrome's default handler state for a given protocol.
+  enum DefaultState {
+    NOT_DEFAULT = 0,

[grt (UTC plus 2), 2012/10/12 19:59:35]

nit: remove " = 0"

[gab, 2012/10/12 20:35:12]

This mimics the enum defined in shell_integration.h, I'd rather keep them as
similar as possible.

[grt (UTC plus 2), 2012/10/15 13:44:33]

I don't think this is necessary since they're independent types (see
GetDefaultWebClientStateFromShellUtilDefaultState).  If you intend for them to
be identical, I suggest you document this with a comment and enforce it with
COMPILE_ASSERT.

[gab, 2012/10/15 14:20:39]

Done.

+    IS_DEFAULT,
+    UNKNOWN_DEFAULT = -1

[grt (UTC plus 2), 2012/10/12 19:59:35]

does this need to be -1?  why not 2?

[gab, 2012/10/12 20:35:12]

Same justification as above.

[grt (UTC plus 2), 2012/10/15 13:44:33]

Would you at least move this above NOT_DEFAULT and get rid of the " = 0" there? 
It's nonsensical to me to have the values out of order like this.

[gab, 2012/10/15 14:20:39]

Done.

+  };
+
   // Typical shortcut directories. Resolved in GetShortcutPath().
   enum ChromeShortcutLocation {
     SHORTCUT_DESKTOP,
@@ -379,6 +386,12 @@ class ShellUtil {
   // Windows prior to Windows 8.
   static bool CanMakeChromeDefaultUnattended();
 
+  // Returns true if Chrome is the default handler for HTTP and HTTPS.
+  static DefaultState IsChromeDefault();
+
+  // Returns true if Chrome is the default handler for |protocol|.
+  static DefaultState IsChromeDefaultProtocolClient(const string16& protocol);
+
   // Make Chrome the default browser. This function works by going through
   // the url protocols and file associations that are related to general
   // browsing, e.g. http, https, .html etc., and requesting to become the