diff --git a/omaha_request_params.cc b/omaha_request_params.cc
index 9f6e82b..03327b2 100644
--- a/omaha_request_params.cc
+++ b/omaha_request_params.cc
@@ -11,16 +11,21 @@
 #include <map>
 #include <string>
 
-#include "base/file_util.h"
-#include "base/string_util.h"
+#include <base/file_util.h>
+#include <base/string_util.h>
+
 #include "update_engine/simple_key_value_store.h"
 #include "update_engine/utils.h"
 
+#define CALL_MEMBER_FN(object, member) ((object).*(member))
+
 using std::map;
 using std::string;
 
 namespace chromeos_update_engine {
 
+const char OmahaRequestParams::kUpdateTrackKey[] = "CHROMEOS_RELEASE_TRACK";
+
 const char* const OmahaRequestParams::kAppId(
     "{87efface-864d-49a5-9bb3-4b050a7c227a}");
 const char* const OmahaRequestParams::kOsPlatform("Chrome OS");
@@ -30,17 +35,24 @@
 
 static const char kHWIDPath[] = "/sys/devices/platform/chromeos_acpi/HWID";
 
+OmahaRequestDeviceParams::OmahaRequestDeviceParams() :
+    force_build_type_(false),
+    forced_official_build_(false) {}
+
 bool OmahaRequestDeviceParams::Init(const std::string& in_app_version,
                                     const std::string& in_update_url) {
   os_platform = OmahaRequestParams::kOsPlatform;
   os_version = OmahaRequestParams::kOsVersion;
   app_version = in_app_version.empty() ?
-      GetLsbValue("CHROMEOS_RELEASE_VERSION", "") : in_app_version;
+      GetLsbValue("CHROMEOS_RELEASE_VERSION", "", NULL) : in_app_version;
   os_sp = app_version + "_" + GetMachineType();
-  os_board = GetLsbValue("CHROMEOS_RELEASE_BOARD", "");
+  os_board = GetLsbValue("CHROMEOS_RELEASE_BOARD", "", NULL);
   app_id = OmahaRequestParams::kAppId;
   app_lang = "en-US";
-  app_track = GetLsbValue("CHROMEOS_RELEASE_TRACK", "");
+  app_track = GetLsbValue(
+      kUpdateTrackKey,
+      "",
+      &chromeos_update_engine::OmahaRequestDeviceParams::IsValidTrack);
   hardware_class = GetHardwareClass();
   struct stat stbuf;
 
@@ -51,13 +63,38 @@
                (errno == ENOENT);
 
   update_url = in_update_url.empty() ?
-      GetLsbValue("CHROMEOS_AUSERVER", OmahaRequestParams::kUpdateUrl) :
+      GetLsbValue("CHROMEOS_AUSERVER", OmahaRequestParams::kUpdateUrl, NULL) :
       in_update_url;
   return true;
 }
 
-string OmahaRequestDeviceParams::GetLsbValue(
-    const string& key, const string& default_value) const {
+bool OmahaRequestDeviceParams::SetTrack(const std::string& track) {
+  TEST_AND_RETURN_FALSE(IsValidTrack(track));
+  FilePath kFile(root_ + utils::kStatefulPartition + "/etc/lsb-release");
+  string file_data;
+  map<string, string> data;
+  if (file_util::ReadFileToString(kFile, &file_data)) {
+    data = simple_key_value_store::ParseString(file_data);
+  }
+  data[kUpdateTrackKey] = track;
+  file_data = simple_key_value_store::AssembleString(data);
+  TEST_AND_RETURN_FALSE(file_util::CreateDirectory(kFile.DirName()));
+  TEST_AND_RETURN_FALSE(
+      file_util::WriteFile(kFile, file_data.data(), file_data.size()) ==
+      static_cast<int>(file_data.size()));
+  app_track = track;
+  return true;
+}
+
+bool OmahaRequestDeviceParams::SetDeviceTrack(const std::string& track) {
+  OmahaRequestDeviceParams params;
+  TEST_AND_RETURN_FALSE(params.Init("", ""));
+  return params.SetTrack(track);
+}
+
+string OmahaRequestDeviceParams::GetLsbValue(const string& key,
+                                             const string& default_value,
+                                             ValueValidator validator) const {
   string files[] = {string(utils::kStatefulPartition) + "/etc/lsb-release",
                     "/etc/lsb-release"};
   for (unsigned int i = 0; i < arraysize(files); ++i) {
@@ -68,8 +105,13 @@
       continue;
 
     map<string, string> data = simple_key_value_store::ParseString(file_data);
-    if (utils::MapContainsKey(data, key))
-      return data[key];
+    if (utils::MapContainsKey(data, key)) {
+      const string& value = data[key];
+      if (validator && !CALL_MEMBER_FN(*this, validator)(value)) {
+        continue;
+      }
+      return value;
+    }
   }
   // not found
   return default_value;
@@ -93,4 +135,18 @@
   return hwid;
 }
 
+bool OmahaRequestDeviceParams::IsOfficialBuild() const {
+  return force_build_type_ ? forced_official_build_ : utils::IsOfficialBuild();
+}
+
+bool OmahaRequestDeviceParams::IsValidTrack(const std::string& track) const {
+  return IsOfficialBuild() ?
+      (track == "beta-channel" || track == "dev-channel") : true;
+}
+
+void OmahaRequestDeviceParams::SetBuildTypeOfficial(bool is_official) {
+  force_build_type_ = true;
+  forced_official_build_ = is_official;
+}
+
 }  // namespace chromeos_update_engine