Add chrome.webstore API methods to allow sites to see progress of installation

chrome/browser/extensions/install_observer.h

Index: chrome/browser/extensions/install_observer.h
diff --git a/chrome/browser/extensions/install_observer.h b/chrome/browser/extensions/install_observer.h
index 6c64cca7e815e66eef55ca3c09ae1f6b92f37e1d..6622dddfd6e9748b9e2296d429a3769e559b7b0b 100644
--- a/chrome/browser/extensions/install_observer.h
+++ b/chrome/browser/extensions/install_observer.h
@@ -33,34 +33,43 @@ class InstallObserver {
 
   // Called at the beginning of the complete installation process, i.e., this
   // is called before the extension download begins.
-  virtual void OnBeginExtensionInstall(const ExtensionInstallParams& params);
+  virtual void OnBeginExtensionInstall(const ExtensionInstallParams& params) {}
+
+  // Called when the Extension begins the download process. This typically
+  // happens right after OnBeginExtensionInstall(), unless the extension has
+  // already been downloaded.
+  virtual void OnBeginExtensionDownload(const std::string& extension_id) {}
 
   // Called whenever the extension download is updated.
   // Note: Some extensions have multiple modules, so the percent included here
   // is a simple calculation of:
   // (finished_files * 100 + current_file_progress) / (total files * 100).
   virtual void OnDownloadProgress(const std::string& extension_id,
-                                  int percent_downloaded);
+                                  int percent_downloaded) {}
+
+  // Called when the necessary downloads have completed, and the crx
+  // installation is due to start.
+  virtual void OnBeginCrxInstall(const std::string& extension_id) {}
 
   // Called if the extension fails to install.
-  virtual void OnInstallFailure(const std::string& extension_id);
+  virtual void OnInstallFailure(const std::string& extension_id) {}
 
   // Called if the installation succeeds.
-  virtual void OnExtensionInstalled(const Extension* extension);
+  virtual void OnExtensionInstalled(const Extension* extension) {}
 
   // Called when an extension is [Loaded, Unloaded, Uninstalled] or an app is
   // installed to the app list. These are simply forwarded from the
   // chrome::NOTIFICATIONs.
-  virtual void OnExtensionLoaded(const Extension* extension);
-  virtual void OnExtensionUnloaded(const Extension* extension);
-  virtual void OnExtensionUninstalled(const Extension* extension);
-  virtual void OnAppInstalledToAppList(const std::string& extension_id);
+  virtual void OnExtensionLoaded(const Extension* extension) {}
+  virtual void OnExtensionUnloaded(const Extension* extension) {}
+  virtual void OnExtensionUninstalled(const Extension* extension) {}
+  virtual void OnAppInstalledToAppList(const std::string& extension_id) {}

[asargent_no_longer_on_chrome, 2014/03/03 18:49:08]

Hmm, some of these stretch the definition of "install". I realize this problem
was present before your changes, but I wonder if we should change the name of
this from InstallObserver to LifeCycleObserver or something like that. 

[Devlin, 2014/03/03 21:15:13]

Good point.  If it's alright, I'll do that change separately right after this
one?  (If we change InstallObserver, we should also change InstallTracker, and
that would mean touching even more files).

If you like, though, I can bundle them in here.

[asargent_no_longer_on_chrome, 2014/03/03 22:25:33]

Separate CL would be fine.

 
   // Called when the app list is reordered.
-  virtual void OnAppsReordered();
+  virtual void OnAppsReordered() {}
 
   // Notifies observers that the observed object is going away.
-  virtual void OnShutdown();
+  virtual void OnShutdown() {}
 
  protected:
   virtual ~InstallObserver() {}