[Metrics] Make MetricsStateManager take a callback param to check if UMA is enabled.

chrome/browser/metrics/metrics_state_manager_unittest.cc

 // Copyright 2014 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/metrics/metrics_state_manager.h"
 
 #include <ctype.h>
 #include <string>
 
+#include "base/bind.h"
 #include "base/command_line.h"
 #include "base/prefs/testing_pref_service.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "components/variations/caching_permuted_entropy_provider.h"
 #include "components/variations/pref_names.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace metrics {
 
 class MetricsStateManagerTest : public testing::Test {
  public:
-  MetricsStateManagerTest() {
+  MetricsStateManagerTest() : is_metrics_reporting_enabled_(false) {
     MetricsStateManager::RegisterPrefs(prefs_.registry());
   }
 
   scoped_ptr<MetricsStateManager> CreateStateManager() {
-    return MetricsStateManager::Create(&prefs_).Pass();
+    return MetricsStateManager::Create(
+        &prefs_,
+        base::Bind(&MetricsStateManagerTest::is_metrics_reporting_enabled,
+                   base::Unretained(this))).Pass();
+  }
+
+  // Sets metrics reporting as enabled for testing.
+  void EnableMetricsReporting() {
+    is_metrics_reporting_enabled_ = true;
   }
 
  protected:
   TestingPrefServiceSimple prefs_;
 
  private:
+  bool is_metrics_reporting_enabled() const {
+    return is_metrics_reporting_enabled_;
+  }
+
+  bool is_metrics_reporting_enabled_;
+
   DISALLOW_COPY_AND_ASSIGN(MetricsStateManagerTest);
 };
 
 // Ensure the ClientId is formatted as expected.
 TEST_F(MetricsStateManagerTest, ClientIdCorrectlyFormatted) {
   scoped_ptr<MetricsStateManager> state_manager(CreateStateManager());
   state_manager->ForceClientIdCreation();
 
   const std::string client_id = state_manager->client_id();
   EXPECT_EQ(36U, client_id.length());
 
   for (size_t i = 0; i < client_id.length(); ++i) {
     char current = client_id[i];
     if (i == 8 || i == 13 || i == 18 || i == 23)
       EXPECT_EQ('-', current);
     else
       EXPECT_TRUE(isxdigit(current));
   }
 }
 
 TEST_F(MetricsStateManagerTest, EntropySourceUsed_Low) {
   scoped_ptr<MetricsStateManager> state_manager(CreateStateManager());
   state_manager->CreateEntropyProvider();
   EXPECT_EQ(MetricsStateManager::ENTROPY_SOURCE_LOW,
             state_manager->entropy_source_returned());
 }
 
 TEST_F(MetricsStateManagerTest, EntropySourceUsed_High) {
-  CommandLine::ForCurrentProcess()->AppendSwitch(
-      switches::kEnableMetricsReportingForTesting);
-
+  EnableMetricsReporting();
   scoped_ptr<MetricsStateManager> state_manager(CreateStateManager());
   state_manager->CreateEntropyProvider();
   EXPECT_EQ(MetricsStateManager::ENTROPY_SOURCE_HIGH,
             state_manager->entropy_source_returned());
 }
 
 TEST_F(MetricsStateManagerTest, LowEntropySource0NotReset) {
   scoped_ptr<MetricsStateManager> state_manager(CreateStateManager());
 
   // Get the low entropy source once, to initialize it.
@@ skipping 77 matching lines @@
 
     state_manager->GetLowEntropySource();
 
     EXPECT_FALSE(prefs_.GetBoolean(::prefs::kMetricsResetIds));
   }
 
   EXPECT_NE(kInitialClientId, prefs_.GetString(::prefs::kMetricsClientID));
 }
 
 }  // namespace metrics