Add a method to read the Omaha experiment_labels value.

This includes updated unit tests.

BUG=160251


Review URL: https://chromiumcodereview.appspot.com/11826028

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@176154 0039d316-1c4b-4281-b951-d872f2087c98

chrome/installer/util/google_update_settings.cc

@@ -668,3 +668,23 @@ bool GoogleUpdateSettings::SetExperimentLabels(
 
   return success;
 }
+
+bool GoogleUpdateSettings::ReadExperimentLabels(
+    bool system_install,
+    string16* experiment_labels) {
+  HKEY reg_root = system_install ? HKEY_LOCAL_MACHINE : HKEY_CURRENT_USER;
+
+  // If this distribution does not set the experiment labels, don't bother
+  // reading.
+  bool success = false;
+  BrowserDistribution* dist = BrowserDistribution::GetDistribution();
+  if (dist->ShouldSetExperimentLabels()) {
+    string16 client_state_path(
+        system_install ? dist->GetStateMediumKey() : dist->GetStateKey());
+    RegKey client_state(reg_root, client_state_path.c_str(), KEY_QUERY_VALUE);
+    success = client_state.ReadValue(google_update::kExperimentLabels,
+                                     experiment_labels) == ERROR_SUCCESS;
+  }
+
+  return success;
+}

chrome/installer/util/google_update_settings.h

@@ -257,6 +257,14 @@ class GoogleUpdateSettings {
   static bool SetExperimentLabels(bool system_install,
                                   const string16& experiment_labels);
 
+  // Reads the Omaha experiment_labels value in the ClientState key for this
+  // Chrome product and writes it into |experiment_labels|. If this distribution
+  // of Chrome does not set the experiment_labels value, this will do nothing to
+  // |experiment_labels|. This will return true if the label was successfully
+  // read.
+  static bool ReadExperimentLabels(bool system_install,
+                                   string16* experiment_labels);
+
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(GoogleUpdateSettings);
 };

chrome/installer/util/google_update_settings_unittest.cc

@@ -119,6 +119,7 @@ class GoogleUpdateSettingsTest : public testing::Test {
     BrowserDistribution* chrome =
         BrowserDistribution::GetSpecificDistribution(
             BrowserDistribution::CHROME_BROWSER);
+    std::wstring value;
 #if defined(GOOGLE_CHROME_BUILD)
     EXPECT_TRUE(chrome->ShouldSetExperimentLabels());
 
@@ -127,7 +128,6 @@ class GoogleUpdateSettingsTest : public testing::Test {
 
     // Validate that something is written. Only worry about the label itself.
     RegKey key;
-    std::wstring value;
     HKEY root = install == SYSTEM_INSTALL ?
         HKEY_LOCAL_MACHINE : HKEY_CURRENT_USER;
     string16 state_key = install == SYSTEM_INSTALL ?
@@ -138,6 +138,9 @@ class GoogleUpdateSettingsTest : public testing::Test {
     EXPECT_EQ(ERROR_SUCCESS,
         key.ReadValue(google_update::kExperimentLabels, &value));
     EXPECT_EQ(kTestExperimentLabel, value);
+    EXPECT_TRUE(GoogleUpdateSettings::ReadExperimentLabels(
+        install == SYSTEM_INSTALL, &value));
+    EXPECT_EQ(kTestExperimentLabel, value);
     key.Close();
 
     // Now that the label is set, test the delete functionality. An empty label
@@ -148,9 +151,13 @@ class GoogleUpdateSettingsTest : public testing::Test {
               key.Open(root, state_key.c_str(), KEY_QUERY_VALUE));
     EXPECT_EQ(ERROR_FILE_NOT_FOUND,
         key.ReadValue(google_update::kExperimentLabels, &value));
+    EXPECT_FALSE(GoogleUpdateSettings::ReadExperimentLabels(
+        install == SYSTEM_INSTALL, &value));
     key.Close();
 #else
     EXPECT_FALSE(chrome->ShouldSetExperimentLabels());
+    EXPECT_FALSE(GoogleUpdateSettings::ReadExperimentLabels(
+        install == SYSTEM_INSTALL, &value));
 #endif  // GOOGLE_CHROME_BUILD
   }