Update extensions with Drag-and-Drop in extension settings page.

chrome/browser/extensions/crx_installer.cc

Index: chrome/browser/extensions/crx_installer.cc
diff --git a/chrome/browser/extensions/crx_installer.cc b/chrome/browser/extensions/crx_installer.cc
index f997fc6fb78ab8869ba650c64851d3f9ff73df52..9300f7f46a2f087be59742b4b247d584175fe965 100644
--- a/chrome/browser/extensions/crx_installer.cc
+++ b/chrome/browser/extensions/crx_installer.cc
@@ -41,6 +41,7 @@
 #include "chrome/common/extensions/extension_file_util.h"
 #include "chrome/common/extensions/extension_icon_set.h"
 #include "chrome/common/extensions/feature_switch.h"
+#include "chrome/common/extensions/permissions/permission_set.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/resource_dispatcher_host.h"
@@ -108,7 +109,8 @@ CrxInstaller::CrxInstaller(
       error_on_unsupported_requirements_(false),
       requirements_checker_(new extensions::RequirementsChecker()),
       has_requirement_errors_(false),
-      install_wait_for_idle_(true) {
+      install_wait_for_idle_(true),
+      show_update_prompt_(false) {
   installer_task_runner_ = frontend_weak->GetFileTaskRunner();
   if (!approval)
     return;
@@ -428,6 +430,13 @@ void CrxInstaller::ConfirmInstall() {
   if (!frontend_weak_.get() || frontend_weak_->browser_terminating())
     return;
 
+  // Limit the extension update with update-prompt only to the updates
+  // initiated from the extension settings page.
+  if (client_ &&
+      off_store_install_allow_reason_ ==
+          OffStoreInstallAllowedFromSettingsPage)
+    CheckExtensionExistsAlready(extension_.get());
+
   string16 error;
   if (!ExtensionSystem::Get(profile_)->management_policy()->
       UserMayLoad(extension_, &error)) {
@@ -454,7 +463,10 @@ void CrxInstaller::ConfirmInstall() {
 
   if (client_ && (!allow_silent_install_ || !approved_)) {
     AddRef();  // Balanced in Proceed() and Abort().
-    client_->ConfirmInstall(this, extension_.get(), show_dialog_callback_);
+    if (show_update_prompt_)
+      client_->ConfirmUpdate(this, extension_.get());
+    else
+      client_->ConfirmInstall(this, extension_.get(), show_dialog_callback_);
   } else {
     if (!installer_task_runner_->PostTask(
             FROM_HERE,
@@ -701,4 +713,35 @@ void CrxInstaller::CleanupTempFiles() {
   }
 }
 
+void CrxInstaller::CheckExtensionExistsAlready(const Extension* extension) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  if (!frontend_weak_.get() || frontend_weak_->browser_terminating())
+    return;
+
+  const Extension* installed_extension =
+      frontend_weak_->GetInstalledExtension(extension->id());
+  if (installed_extension) {
+    // Previous version of the extension exists.
+    expected_id_ = installed_extension->id();
+    install_source_ = installed_extension->location();
+    install_cause_ = extension_misc::INSTALL_CAUSE_UPDATE;
+
+    // Update prompt is shown only if the extension has requested for
+    // additional permissions.
+    scoped_refptr<PermissionSet> granted_permissions =
+        frontend_weak_->extension_prefs()->GetGrantedPermissions(
+            installed_extension->id());
+    CHECK(granted_permissions.get());
+    show_update_prompt_ = granted_permissions->HasLessPrivilegesThan(
+        extension->GetActivePermissions());
+    if (!show_update_prompt_) {
+      allow_silent_install_ = true;
+      approved_ = true;
+    }
+
+    // Suppress the UI after success or failure.
+    client_->install_ui()->SetSkipPostInstallUI(true);
+  }
+}
+
 }  // namespace extensions