Support for interactive set-chrome-as-default in Windows.

chrome/browser/shell_integration.h

Index: chrome/browser/shell_integration.h
diff --git a/chrome/browser/shell_integration.h b/chrome/browser/shell_integration.h
index 3a0b3ab052689e444505d79ece8d3f1a2fb7df73..4d81ff242bccfce0c28a087bc41a23a0a8c7607d 100644
--- a/chrome/browser/shell_integration.h
+++ b/chrome/browser/shell_integration.h
@@ -23,16 +23,30 @@ class ShellIntegration {
   // false if this operation fails.
   static bool SetAsDefaultBrowser();
 
+  // Initializes an OS shell flow which (if followed by the user) should set
+  // Chrome as the default browser. Returns false if the flow cannot be
+  // initialized or if it is not supported (introduced for Windows 8).
+  static bool StartSetAsDefaultBrowserInteractive();

[grt (UTC plus 2), 2012/05/28 20:47:02]

The name "StartBlaBlah" makes me think that this might kick off an async
operation.  is this the case, or is it a blocking operation?  please document
one way or the other.

Should the comment really begin with "Initiates" rather than "Initializes"?  If
the function returns true, does the caller need to know anything about how the
OS shell flow terminates?

How about when the function returns false?  Is that only due to an error?

Must this only be called from a certain thread?

[motek., 2012/05/31 21:59:04]

Done.

+
   // Sets Chrome as the default client application for the given protocol
   // (only for the current user). Returns false if this operation fails.
   static bool SetAsDefaultProtocolClient(const std::string& protocol);
 
-  // Returns true if the running browser can be set as the default browser.
-  static bool CanSetAsDefaultBrowser();
+  // In Windows 8 a browser can be made default-in-metro only in an interactive
+  // flow. We will distinguish between two types of permissions here to avoid
+  // forcing the user into UI interaction when this should not be done.
+  enum DefaultSettingsChangePermission {
+    CHANGE_DEFAULT_NOT_ALLOWED = 0,
+    CHANGE_DEFAULT_UNATTENDED,
+    CHANGE_DEFAULT_INTERACTIVE,
+  };
+
+  // Returns requirements for making the running browser the user's default.
+  static DefaultSettingsChangePermission CanSetAsDefaultBrowser();
 
-  // Returns true if the running browser can be set as the default client
-  // application for specific protocols.
-  static bool CanSetAsDefaultProtocolClient();
+  // Returns requirements for making the running browser the user's default
+  // client application for specific protocols.
+  static DefaultSettingsChangePermission CanSetAsDefaultProtocolClient();
 
   // On Linux, it may not be possible to determine or set the default browser
   // on some desktop environments or configurations. So, we use this enum and