Add field trial for the WebAPK server URL

chrome/browser/android/webapk/webapk_installer.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/android/webapk/webapk_installer.h"
 
 #include "base/android/build_info.h"
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
 #include "base/android/path_utils.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/task_runner_util.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "chrome/browser/android/shortcut_helper.h"
 #include "chrome/browser/android/webapk/webapk.pb.h"
 #include "chrome/browser/android/webapk/webapk_icon_hasher.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/common/chrome_features.h"
 #include "chrome/common/chrome_switches.h"
+#include "components/variations/variations_associated_data.h"
 #include "components/version_info/version_info.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/common/manifest_util.h"
 #include "jni/WebApkInstaller_jni.h"
 #include "net/http/http_status_code.h"
 #include "net/url_request/url_fetcher.h"
 #include "ui/gfx/codec/png_codec.h"
 #include "url/gurl.h"
 
 namespace {
 
 // The default WebAPK server URL.
-const char kDefaultWebApkServerUrl[] =
+const char kDefaultServerUrl[] =
     "https://webapk.googleapis.com/v1alpha/webApks/?alt=proto";
 
+// Flag for setting the WebAPK server URL.
+const char kServerUrlVariationsParamKey[] = "ServerUrl";
+
 // The MIME type of the POST data sent to the server.
 const char kProtoMimeType[] = "application/x-protobuf";
 
 // The default number of milliseconds to wait for the WebAPK download URL from
 // the WebAPK server.
 const int kWebApkDownloadUrlTimeoutMs = 60000;
 
 // The default number of milliseconds to wait for the WebAPK download to
 // complete.
 const int kDownloadTimeoutMs = 60000;
 
 const int kWorldReadableFilePermission = base::FILE_PERMISSION_READ_BY_USER |
                                          base::FILE_PERMISSION_READ_BY_GROUP |
                                          base::FILE_PERMISSION_READ_BY_OTHERS;
 
+// Returns the WebAPK server URL based on the command line flags and the
+// currently active field trials.
+GURL GetServerUrl() {
+  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
+  if (command_line->HasSwitch(switches::kWebApkServerUrl))
+    return GURL(command_line->GetSwitchValueASCII(switches::kWebApkServerUrl));

[dominickn, 2016/10/24 00:32:37]

For safety, should you test whether this GURL is_valid() and return the empty
GURL if so? And then don't initiate the network request if the URL is no good?

[pkotwicz, 2016/10/24 04:33:42]

Good point.

UrlFetcher crashes if given an invalid URL

+  std::string server_url = variations::GetVariationParamValueByFeature(
+      features::kWebApk, kServerUrlVariationsParamKey);
+  return GURL(!server_url.empty() ? server_url : kDefaultServerUrl);
+}
+
 // Returns the scope from |info| if it is specified. Otherwise, returns the
 // default scope.
 GURL GetScope(const ShortcutInfo& info) {
   return (info.scope.is_valid())
       ? info.scope
       : ShortcutHelper::GetScopeFromURL(info.url);
 }
 
 // Converts a color from the format specified in content::Manifest to a CSS
 // string.
@@ skipping 87 matching lines @@
 
   return output_dir;
 }
 
 }  // anonymous namespace
 
 WebApkInstaller::WebApkInstaller(const ShortcutInfo& shortcut_info,
                                  const SkBitmap& shortcut_icon)
     : shortcut_info_(shortcut_info),
       shortcut_icon_(shortcut_icon),
+      server_url_(GetServerUrl()),
       webapk_download_url_timeout_ms_(kWebApkDownloadUrlTimeoutMs),
       download_timeout_ms_(kDownloadTimeoutMs),
       task_type_(UNDEFINED),
       weak_ptr_factory_(this) {
-  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
-  server_url_ =
-      GURL(command_line->HasSwitch(switches::kWebApkServerUrl)
-               ? command_line->GetSwitchValueASCII(switches::kWebApkServerUrl)
-               : kDefaultWebApkServerUrl);
   CreateJavaRef();
 }
 
 void WebApkInstaller::CreateJavaRef() {
   JNIEnv* env = base::android::AttachCurrentThread();
   java_ref_.Reset(Java_WebApkInstaller_create(
       env, reinterpret_cast<intptr_t>(this)));
 }
 
 WebApkInstaller::~WebApkInstaller() {
@@ skipping 292 matching lines @@
 
 void WebApkInstaller::OnSuccess() {
   finish_callback_.Run(true, webapk_package_);
   delete this;
 }
 
 void WebApkInstaller::OnFailure() {
   finish_callback_.Run(false, webapk_package_);
   delete this;
 }