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

chrome/browser/extensions/install_tracker.cc

Index: chrome/browser/extensions/install_tracker.cc
diff --git a/chrome/browser/extensions/install_tracker.cc b/chrome/browser/extensions/install_tracker.cc
index 0c79c1cbae0aaebba06b3fc8b032e80e9192b2c0..fc5b5049763690cfa618fea05189d8d9544af2dd 100644
--- a/chrome/browser/extensions/install_tracker.cc
+++ b/chrome/browser/extensions/install_tracker.cc
@@ -56,12 +56,22 @@ void InstallTracker::OnBeginExtensionInstall(
                     OnBeginExtensionInstall(params));
 }
 
+void InstallTracker::OnBeginExtensionDownload(const std::string& extension_id) {
+  FOR_EACH_OBSERVER(
+      InstallObserver, observers_, OnBeginExtensionDownload(extension_id));
+}
+
 void InstallTracker::OnDownloadProgress(const std::string& extension_id,
                                         int percent_downloaded) {
   FOR_EACH_OBSERVER(InstallObserver, observers_,
                     OnDownloadProgress(extension_id, percent_downloaded));
 }
 
+void InstallTracker::OnBeginCrxInstall(const std::string& extension_id) {
+  FOR_EACH_OBSERVER(
+      InstallObserver, observers_, OnBeginCrxInstall(extension_id));
+}
+
 void InstallTracker::OnInstallFailure(
     const std::string& extension_id) {
   FOR_EACH_OBSERVER(InstallObserver, observers_,