Change uses of base::JoinString to pass StringPieces where possible.

content/renderer/input/main_thread_event_queue_unittest.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 <stddef.h>
 
 #include <new>
 #include <utility>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/metrics/field_trial.h"
+#include "base/strings/string_piece.h"
 #include "base/strings/string_util.h"
 #include "base/test/histogram_tester.h"
 #include "base/test/scoped_feature_list.h"
 #include "base/test/test_simple_task_runner.h"
 #include "build/build_config.h"
 #include "content/common/input/synthetic_web_input_event_builders.h"
 #include "content/renderer/input/main_thread_event_queue.h"
 #include "content/renderer/render_thread_impl.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/WebKit/public/platform/scheduler/test/mock_renderer_scheduler.h"
@@ skipping 28 matching lines @@
 
 }  // namespace
 
 class MainThreadEventQueueTest : public testing::TestWithParam<unsigned>,
                                  public MainThreadEventQueueClient {
  public:
   MainThreadEventQueueTest()
       : main_task_runner_(new base::TestSimpleTaskRunner()),
         raf_aligned_input_setting_(GetParam()),
         needs_main_frame_(false) {
-    std::vector<std::string> features;
-    std::vector<std::string> disabled_features;
+    std::vector<base::StringPiece> features;
+    std::vector<base::StringPiece> disabled_features;
     if (raf_aligned_input_setting_ & kRafAlignedEnabledTouch) {
       features.push_back(features::kRafAlignedTouchInputEvents.name);
     } else {
       disabled_features.push_back(features::kRafAlignedTouchInputEvents.name);
     }
     if (raf_aligned_input_setting_ & kRafAlignedEnabledMouse) {
       features.push_back(features::kRafAlignedMouseInputEvents.name);
     } else {
       disabled_features.push_back(features::kRafAlignedMouseInputEvents.name);
     }
@@ skipping 756 matching lines @@
       "MainThreadResponsivenessScrollIntervention", "Control");
   queue_ = new MainThreadEventQueue(kTestRoutingID,
                                     &dummy_main_thread_event_queue_client_,
                                     main_task_runner_, &renderer_scheduler_);
   EXPECT_FALSE(enable_non_blocking_due_to_main_thread_responsiveness_flag());
   EXPECT_EQ(base::TimeDelta::FromMilliseconds(0),
             main_thread_responsiveness_threshold());
 }
 
 }  // namespace content