Replace early check for PNaCl with an on-demand check.

chrome/browser/component_updater/pnacl/pnacl_component_installer.h

Index: chrome/browser/component_updater/pnacl/pnacl_component_installer.h
diff --git a/chrome/browser/component_updater/pnacl/pnacl_component_installer.h b/chrome/browser/component_updater/pnacl/pnacl_component_installer.h
index 9ba2997297b63ce6c0fd64f75b84c4a0b6bf97d1..952cbfcfc255ca4dcb75eda6ea76b9d6b9d46e39 100644
--- a/chrome/browser/component_updater/pnacl/pnacl_component_installer.h
+++ b/chrome/browser/component_updater/pnacl/pnacl_component_installer.h
@@ -5,6 +5,9 @@
 #ifndef CHROME_BROWSER_COMPONENT_UPDATER_PNACL_PNACL_COMPONENT_INSTALLER_H_
 #define CHROME_BROWSER_COMPONENT_UPDATER_PNACL_PNACL_COMPONENT_INSTALLER_H_
 
+#include <list>
+
+#include "base/callback_forward.h"
 #include "base/files/file_path.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/version.h"
@@ -53,12 +56,26 @@ class PnaclComponentInstaller : public ComponentInstaller {
 
   ComponentUpdateService* cus() const { return cus_; }
 
+  typedef base::Callback<void(bool)> InstallCallback;
+  void AddInstallCallback(const InstallCallback& cb);
+
  private:
+  // Cancel a particular callback after a timeout.
+  void CancelCallback(int callback_num);
+
+  void NotifyAllWithResult(bool status);
+  void NotifyInstallError();
+  void NotifyInstallSuccess();
+
   bool per_user_;
   scoped_ptr<PnaclProfileObserver> profile_observer_;
   base::FilePath current_profile_path_;
   base::Version current_version_;
   ComponentUpdateService* cus_;
+  // Counter to issue identifiers to each callback.
+  int callback_nums_;
+  // List of callbacks to issue when an install completes successfully.
+  std::list<std::pair<InstallCallback, int> > install_callbacks_;
   DISALLOW_COPY_AND_ASSIGN(PnaclComponentInstaller);
 };
 
@@ -67,4 +84,11 @@ class PnaclComponentInstaller : public ComponentInstaller {
 bool CheckPnaclComponentManifest(const base::DictionaryValue& manifest,
                                  base::Version* version_out);
 
+// Ask the given component updater service to do a first-install for PNaCl.
+// The |installed| callback will be run with |true| on success,
+// or run with |false| on an error. The callback is called on the UI thread.
+void RequestFirstInstall(ComponentUpdateService* cus,
+                         PnaclComponentInstaller* pci,
+                         const base::Callback<void(bool)>& installed);
+
 #endif  // CHROME_BROWSER_COMPONENT_UPDATER_PNACL_PNACL_COMPONENT_INSTALLER_H_