Add support for uninstalling components and use it in SupervisedUserWhitelistInstaller.

chrome/browser/component_updater/supervised_user_whitelist_installer.cc

Index: chrome/browser/component_updater/supervised_user_whitelist_installer.cc
diff --git a/chrome/browser/component_updater/supervised_user_whitelist_installer.cc b/chrome/browser/component_updater/supervised_user_whitelist_installer.cc
index 55b08602d7840b1c1e6a0651225190aaa467295b..49b55c3037bb6182288ed28348031ea852fc8482 100644
--- a/chrome/browser/component_updater/supervised_user_whitelist_installer.cc
+++ b/chrome/browser/component_updater/supervised_user_whitelist_installer.cc
@@ -121,9 +121,10 @@ class SupervisedUserWhitelistInstallerImpl
                          const std::string& name,
                          bool newly_added,
                          const WhitelistReadyCallback& callback) override;
-  void UnregisterWhitelist(const std::string& crx_id) override;
+  void UninstallWhitelist(const std::string& crx_id) override;
 
   ComponentUpdateService* cus_;
+  std::map<std::string, scoped_refptr<DefaultComponentInstaller>> installers_;
 };
 
 SupervisedUserWhitelistInstallerImpl::SupervisedUserWhitelistInstallerImpl(
@@ -144,14 +145,18 @@ void SupervisedUserWhitelistInstallerImpl::RegisterWhitelist(
 
   installer->Register(cus_);
 
+  installers_[crx_id] = installer;

[Sorin Jianu, 2015/02/05 22:55:35]

Do we have many crx ids associated with this product? How does this work?

[Bernhard Bauer, 2015/02/05 23:57:34]

Yeah, there can be multiple whitelists, each with their own CRX ID.

In terms of functionality, the effect will be the union of all the installed
whitelists.

[Sorin Jianu, 2015/02/06 00:22:04]

Do we have an idea about how many whitelists are we talking about? Can you also
point me out to any design documentation for this product?
We want to make sure that our system can scale to this design. The idea is that
unlike extensions, we expect to manage fewer components. I'd like to get an idea
how far we are pushing the envelope here.

[Bernhard Bauer, 2015/02/06 16:05:05]

The design doc is at go/unichrome-whitelists-clank.

I would expect the number of whitelists to be single-digit, although it's of
course hard to predict this. In part what we want to do is get an initial
version of this out for dogfooding and gather data based on that. I'll add some
metrics for the number of whitelists and whitelist installation/uninstallation
actions (see https://codereview.chromium.org/905763002/).

Also, what area exactly are you concerned about in terms of performance? Maybe
there is something to optimize there.

+
   if (newly_added)
     TriggerComponentUpdate(&cus_->GetOnDemandUpdater(), crx_id);
 }
 
-void SupervisedUserWhitelistInstallerImpl::UnregisterWhitelist(
-    const std::string& id) {
-  // TODO(bauerb): Implement!
-  NOTIMPLEMENTED();
+void SupervisedUserWhitelistInstallerImpl::UninstallWhitelist(
+    const std::string& crx_id) {
+  auto it = installers_.find(crx_id);
+  DCHECK(it != installers_.end());
+  it->second->Unregister(cus_);
+  installers_.erase(it);
 }
 
 }  // namespace