Allow chrome to become the os default handler for arbitrary protocols on mac/win.

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 575575e9175ecc92cc9f805e1c3f5acca2e4febd..b91d7db6fc0be05e1a31486fd84fa29fde06dfd4 100644
--- a/chrome/browser/shell_integration.h
+++ b/chrome/browser/shell_integration.h
@@ -30,26 +30,35 @@ class ShellIntegration {
   // this operation fails.
   static bool SetAsDefaultBrowser();
 
+  // Sets Chrome as client application for the given protocol (only for
+  // current user). Returns false if this operation fails.
+  static bool SetAsDefaultProtocolClient(const std::string& protocol);
+
   // 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
   // not a plain bool. (Note however that if used like a bool, this enum will
   // have reasonable behavior.)
-  enum DefaultBrowserState {
-    NOT_DEFAULT_BROWSER = 0,
-    IS_DEFAULT_BROWSER,
-    UNKNOWN_DEFAULT_BROWSER
+  enum DefaultClientAppState {

[Mark Mentovai, 2011/05/23 00:23:52]

In isolation, DefaultClientAppState doesn’t tell me anything about this being
used as “default client for a URL protocol.” Maybe the name should have the word
“protocol” in it as you’ve done with SetAsDefaultProtocolClient,
IsDefaultProtocolClient, and CanSetAsDefaultProtocolClient. As it stands now,
for all anyone knows, DefaultClientAppState could just as well mean something
like “do I start maximized?”

[benwells, 2011/05/23 06:08:37]

Agreed, it doesn't say enough. I avoided the word 'protocol' as the default
browser is not exactly a default protocol handler, it is the default handler for
two protocols plus some extra stuff depending on the OS.

I will update to DefaultWebClientState.

On 2011/05/23 00:23:52, Mark Mentovai wrote:

[benwells, 2011/05/24 06:10:38]

Done.

+    NOT_DEFAULT_CLIENT_APP = 0,
+    IS_DEFAULT_CLIENT_APP,
+    UNKNOWN_DEFAULT_CLIENT_APP

[Mark Mentovai, 2011/05/23 00:23:52]

My own preference would be for the UNKNOWN element to have value -1.

[benwells, 2011/05/24 06:10:38]

Done.

   };
 
   // Attempt to determine if this instance of Chrome is the default browser and
   // return the appropriate state. (Defined as being the handler for HTTP/HTTPS
   // protocols; we don't want to report "no" here if the user has simply chosen
   // to open HTML files in a text editor and FTP links with an FTP client.)
-  static DefaultBrowserState IsDefaultBrowser();
+  static DefaultClientAppState IsDefaultBrowser();
 
   // Returns true if Firefox is likely to be the default browser for the current
   // user. This method is very fast so it can be invoked in the UI thread.
   static bool IsFirefoxDefaultBrowser();
 
+  // Attempt to determine if this instance of Chrome is the default client
+  // application for the given protocol and return the appropriate state.
+  static DefaultClientAppState
+      IsDefaultProtocolClient(const std::string& protocol);
+
   struct ShortcutInfo {
     ShortcutInfo();
     ~ShortcutInfo();
@@ -123,65 +132,70 @@ class ShellIntegration {
   static void MigrateChromiumShortcuts();
 #endif  // defined(OS_WIN)
 
-  // The current default browser UI state
-  enum DefaultBrowserUIState {
+  // The current default browser / client application UI state
+  enum DefaultClientAppUIState {
     STATE_PROCESSING,
     STATE_NOT_DEFAULT,
     STATE_IS_DEFAULT,
     STATE_UNKNOWN
   };
 
-  class DefaultBrowserObserver {
+  class DefaultClientAppObserver {
    public:
     // Updates the UI state to reflect the current default browser state.
-    virtual void SetDefaultBrowserUIState(DefaultBrowserUIState state) = 0;
-    virtual ~DefaultBrowserObserver() {}
+    virtual void SetDefaultClientAppUIState(DefaultClientAppUIState state) = 0;
+    virtual ~DefaultClientAppObserver() {}
   };
-  //  A helper object that handles checking if Chrome is the default browser on
-  //  Windows and also setting it as the default browser. These operations are
-  //  performed asynchronously on the file thread since registry access is
-  //  involved and this can be slow.
-  //
-  class DefaultBrowserWorker
-      : public base::RefCountedThreadSafe<DefaultBrowserWorker> {
+  //  A helper object that handles checking if Chrome is the default browser
+  //  or application for a url protocol on Windows and Linux, and also setting
+  //  it as the default. These operations are performed asynchronously on the
+  //  file thread since registry access is involved and this can be slow.

[Mark Mentovai, 2011/05/23 00:23:52]

Any comment in this file that mentions the “registry” should be revised to use
more generic language than “registry” or should limit what it says about the
registry to Windows.

This is not the only occurrence in this file.

[benwells, 2011/05/24 06:10:38]

Done.

+  class DefaultClientAppWorker

[Mark Mentovai, 2011/05/23 00:23:52]

I believe that this interface is now too cumbersome to be part of
ShellIntegration’s public API. A DefaultClientAppWorker is now an object that
can behave in four different ways depending on which of the four Start methods
is called. There doesn’t appear to be any protection against calling more than
one of them on a single object, although doing so would be hazardous.

At this point, I believe that this needs to be refactored to either make the
bulk of this class an internal (and hidden) implementation detail of
ShellIntegration, or to provide distinct classes for the DefaultBrowser and
DefaultProtocolClient operations (perhaps descended from a common base), or
both.

[benwells, 2011/05/23 06:08:37]

Yes, there would be some hazard if you tried to re-use the same object.
Refactoring so that there are two classes, with the protocol client class being
constructed with the protocol, might be the best approach.

On 2011/05/23 00:23:52, Mark Mentovai wrote:

[benwells, 2011/05/24 06:10:38]

Done.

+      : public base::RefCountedThreadSafe<DefaultClientAppWorker> {
    public:
-    explicit DefaultBrowserWorker(DefaultBrowserObserver* observer);
+    explicit DefaultClientAppWorker(DefaultClientAppObserver* observer);
 
-    // Checks if Chrome is the default browser.
+    // Checks to see if Chrome is the default browser or protocol client.
     void StartCheckDefaultBrowser();
+    void StartCheckDefaultProtocolClient(const std::string& protocol);
 
-    // Sets Chrome as the default browser.
+    // Sets Chrome as the default browser or protocol client.
     void StartSetAsDefaultBrowser();
+    void StartSetAsDefaultProtocolClient(const std::string& protocol);
 
     // Called to notify the worker that the view is gone.
     void ObserverDestroyed();
 
    private:
-    friend class base::RefCountedThreadSafe<DefaultBrowserWorker>;
+    friend class base::RefCountedThreadSafe<DefaultClientAppWorker>;
 
-    virtual ~DefaultBrowserWorker() {}
+    virtual ~DefaultClientAppWorker() {}
 
     // Functions that track the process of checking if Chrome is the default
-    // browser.  |ExecuteCheckDefaultBrowser| checks the registry on the file
-    // thread.  |CompleteCheckDefaultBrowser| notifies the view to update on the
+    // browser.  |ExecuteCheckDefault*| checks the registry on the file thread.
+    // |CompleteCheckDefaultApplication| notifies the view to update on the
     // UI thread.
     void ExecuteCheckDefaultBrowser();
-    void CompleteCheckDefaultBrowser(DefaultBrowserState state);
+    void ExecuteCheckDefaultProtocolClient();
+    void CompleteCheckDefaultApplication(DefaultClientAppState state);
 
     // Functions that track the process of setting Chrome as the default
-    // browser.  |ExecuteSetAsDefaultBrowser| updates the registry on the file
-    // thread.  |CompleteSetAsDefaultBrowser| notifies the view to update on the
+    // browser.  |ExecuteSetAsDefault*| updates the registry on the file
+    // thread.  |CompleteSetAsDefault*| notifies the view to update on the
     // UI thread.
     void ExecuteSetAsDefaultBrowser();
+    void ExecuteSetAsDefaultProtocolClient();
     void CompleteSetAsDefaultBrowser();
+    void CompleteSetAsDefaultProtocolClient();
 
     // Updates the UI in our associated view with the current default browser
     // state.
-    void UpdateUI(DefaultBrowserState state);
+    void UpdateUI(DefaultClientAppState state);
 
-    DefaultBrowserObserver* observer_;
+    DefaultClientAppObserver* observer_;
+    std::string protocol_;
 
-    DISALLOW_COPY_AND_ASSIGN(DefaultBrowserWorker);
+    DISALLOW_COPY_AND_ASSIGN(DefaultClientAppWorker);
   };
 };