Download webstore CRXs into separate directory.

chrome/browser/extensions/webstore_installer.cc

Index: chrome/browser/extensions/webstore_installer.cc
diff --git a/chrome/browser/extensions/webstore_installer.cc b/chrome/browser/extensions/webstore_installer.cc
index 5ef853c25f2366f8bdb027dc77f7aafa3a7ad644..40b977685948cd2de8dc727e0b406eff77ced810 100644
--- a/chrome/browser/extensions/webstore_installer.cc
+++ b/chrome/browser/extensions/webstore_installer.cc
@@ -10,6 +10,8 @@
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/file_util.h"
+#include "base/metrics/field_trial.h"
+#include "base/path_service.h"
 #include "base/rand_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
@@ -27,6 +29,7 @@
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser_list.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
+#include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/extensions/extension_constants.h"
@@ -79,6 +82,11 @@ const char kInlineInstallSource[] = "inline";
 const char kDefaultInstallSource[] = "ondemand";
 const char kAppLauncherInstallSource[] = "applauncher";
 
+// Folder for downloading crx files from the webstore. This is used so that the
+// crx files don't go via the usual downloads folder.
+const base::FilePath::CharType kWebstoreDownloadFolder[] =
+    FILE_PATH_LITERAL("Webstore Downloads");
+
 base::FilePath* g_download_directory_for_tests = NULL;
 
 // Must be executed on the FILE thread.
@@ -125,6 +133,16 @@ void GetDownloadFilePath(
                           base::Bind(callback, file));
 }
 
+bool UseSeparateWebstoreDownloadDirectory() {
+  const char kWebstoreDownloadDirectoryFieldTrialName[] =
+      "WebstoreDownloadDirectory";
+  const char kSeparateDirectoryUnderUDD[] = "SeparateDirectoryUnderUDD";
+
+  std::string field_trial_group = base::FieldTrialList::FindFullName(
+      kWebstoreDownloadDirectoryFieldTrialName);
+  return field_trial_group == kSeparateDirectoryUnderUDD;
+}
+
 }  // namespace
 
 namespace extensions {
@@ -487,8 +505,17 @@ void WebstoreInstaller::DownloadNextPendingModule() {
 void WebstoreInstaller::DownloadCrx(
     const std::string& extension_id, InstallSource source) {
   download_url_ = GetWebstoreInstallURL(extension_id, source);
-  base::FilePath download_path = DownloadPrefs::FromDownloadManager(
-      BrowserContext::GetDownloadManager(profile_))->DownloadPath();
+
+  base::FilePath download_path;
+  if (UseSeparateWebstoreDownloadDirectory()) {
+    base::FilePath user_data_dir;
+    PathService::Get(chrome::DIR_USER_DATA, &user_data_dir);
+    download_path = user_data_dir.Append(kWebstoreDownloadFolder);
+  } else {
+    download_path = DownloadPrefs::FromDownloadManager(
+        BrowserContext::GetDownloadManager(profile_))->DownloadPath();
+  }
+
   BrowserThread::PostTask(
       BrowserThread::FILE, FROM_HERE,
       base::Bind(&GetDownloadFilePath, download_path, id_,