Adds a webstorePrivate method for silently installing extensions.

chrome/browser/extensions/extension_webstore_private_apitest.cc

Index: chrome/browser/extensions/extension_webstore_private_apitest.cc
diff --git a/chrome/browser/extensions/extension_webstore_private_apitest.cc b/chrome/browser/extensions/extension_webstore_private_apitest.cc
index d7fbf65a7050d69733c5cb82cea3d79e1cc93996..ec28b22c9393bd5c133c82343afd3e59e1849d20 100644
--- a/chrome/browser/extensions/extension_webstore_private_apitest.cc
+++ b/chrome/browser/extensions/extension_webstore_private_apitest.cc
@@ -20,6 +20,9 @@
 
 namespace {
 
+const char* kExtensionID = "enfkhcelefdadlmkffamgdlgplcionje";
+const char* kAppID = "iladmdjkfniedhfhcfoefgojhgaiaccc";
+
 class WebstoreInstallListener : public WebstoreInstaller::Delegate {
  public:
   WebstoreInstallListener()
@@ -170,7 +173,7 @@ IN_PROC_BROWSER_TEST_F(ExtensionWebstorePrivateApiTest,
   ASSERT_TRUE(RunInstallTest("app_install_bubble.html", "app.crx"));
   listener.Wait();
   ASSERT_TRUE(listener.received_success());
-  ASSERT_EQ("iladmdjkfniedhfhcfoefgojhgaiaccc", listener.id());
+  ASSERT_EQ(kAppID, listener.id());
 }
 
 // Tests using the iconUrl parameter to the install function.
@@ -178,3 +181,9 @@ IN_PROC_BROWSER_TEST_F(ExtensionWebstorePrivateApiTest,
                        IconUrl) {
   ASSERT_TRUE(RunInstallTest("icon_url.html", "extension.crx"));
 }
+
+// Tests using silentlyInstall to install extensions.
+IN_PROC_BROWSER_TEST_F(ExtensionWebstorePrivateApiTest, SilentlyInstall) {
+  WebstorePrivateApi::SetTrustedIDForTesting(kExtensionID);
+  ASSERT_TRUE(RunInstallTest("silently_install.html", "extension.crx"));
+}