Use movable types for CallStackProfile(s) to remove copying of data.

components/metrics/child_call_stack_profile_collector_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 "components/metrics/child_call_stack_profile_collector.h"
 
 #include <memory>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 17 matching lines @@
   class Receiver : public mojom::CallStackProfileCollector {
    public:
     using CallStackProfile = base::StackSamplingProfiler::CallStackProfile;
 
     Receiver(mojom::CallStackProfileCollectorRequest request)
         : binding_(this, std::move(request)) {}
     ~Receiver() override {}
 
     void Collect(const CallStackProfileParams& params,
                  base::TimeTicks start_timestamp,
-                 const std::vector<CallStackProfile>& profiles) override {
+                 std::vector<CallStackProfile> profiles) override {
       this->profiles.push_back(ChildCallStackProfileCollector::ProfilesState(
           params,
           start_timestamp,
-          profiles));
+          std::move(profiles)));
     }
 
     std::vector<ChildCallStackProfileCollector::ProfilesState> profiles;
 
    private:
     mojo::Binding<mojom::CallStackProfileCollector> binding_;
 
     DISALLOW_COPY_AND_ASSIGN(Receiver);
   };
 
   ChildCallStackProfileCollectorTest()
       : receiver_impl_(new Receiver(GetProxy(&receiver_))) {}
 
   void CollectProfiles(

[Mike Wittman, 2016/10/21 18:05:29]

This function can be removed.

[bcwhite, 2016/10/24 13:17:45]

Done.

       const CallStackProfileParams& params,
-      const base::StackSamplingProfiler::CallStackProfiles& profiles) {
-    child_collector_.GetProfilerCallback(params).Run(profiles);
+      base::StackSamplingProfiler::CallStackProfiles profiles) {
+    child_collector_.GetProfilerCallback(params).Run(std::move(profiles));
+  }
+
+  void CollectEmptyProfiles(
+      const CallStackProfileParams& params,
+      size_t profile_count) {
+    base::StackSamplingProfiler::CallStackProfiles profiles;
+    for (size_t i = 0; i < profile_count; ++i)
+      profiles.push_back(base::StackSamplingProfiler::CallStackProfile());
+    child_collector_.GetProfilerCallback(params).Run(std::move(profiles));
   }
 
   const std::vector<ChildCallStackProfileCollector::ProfilesState>&
   profiles() const {
     return child_collector_.profiles_;
   }
 
   base::MessageLoop loop_;
   mojom::CallStackProfileCollectorPtr receiver_;
   std::unique_ptr<Receiver> receiver_impl_;
   ChildCallStackProfileCollector child_collector_;
 
   DISALLOW_COPY_AND_ASSIGN(ChildCallStackProfileCollectorTest);
 };
 
 // Test the behavior when an interface is provided.
 TEST_F(ChildCallStackProfileCollectorTest, InterfaceProvided) {
   EXPECT_EQ(0u, profiles().size());
 
   // Add profiles before providing the interface.
-  CollectProfiles(
+  CollectEmptyProfiles(
       CallStackProfileParams(CallStackProfileParams::BROWSER_PROCESS,
                              CallStackProfileParams::UI_THREAD,
                              CallStackProfileParams::JANKY_TASK,
                              CallStackProfileParams::PRESERVE_ORDER),
-      { base::StackSamplingProfiler::CallStackProfile(),
-            base::StackSamplingProfiler::CallStackProfile() });
+      2);
   ASSERT_EQ(1u, profiles().size());
   EXPECT_EQ(CallStackProfileParams::BROWSER_PROCESS,
             profiles()[0].params.process);
   EXPECT_EQ(CallStackProfileParams::UI_THREAD, profiles()[0].params.thread);
   EXPECT_EQ(CallStackProfileParams::JANKY_TASK, profiles()[0].params.trigger);
   EXPECT_EQ(CallStackProfileParams::PRESERVE_ORDER,
             profiles()[0].params.ordering_spec);
   base::TimeTicks start_timestamp = profiles()[0].start_timestamp;
   EXPECT_GE(base::TimeDelta::FromMilliseconds(10),
             base::TimeTicks::Now() - start_timestamp);
   EXPECT_EQ(2u, profiles()[0].profiles.size());
 
   // Set the interface. The profiles should be passed to it.
   child_collector_.SetParentProfileCollector(std::move(receiver_));
   base::RunLoop().RunUntilIdle();
   EXPECT_EQ(0u, profiles().size());
   ASSERT_EQ(1u, receiver_impl_->profiles.size());
   EXPECT_EQ(CallStackProfileParams::JANKY_TASK,
             receiver_impl_->profiles[0].params.trigger);
   EXPECT_EQ(CallStackProfileParams::PRESERVE_ORDER,
             receiver_impl_->profiles[0].params.ordering_spec);
   EXPECT_EQ(start_timestamp, receiver_impl_->profiles[0].start_timestamp);
   EXPECT_EQ(2u, receiver_impl_->profiles[0].profiles.size());
 
   // Add profiles after providing the interface. They should also be passed to
   // it.
   receiver_impl_->profiles.clear();
-  CollectProfiles(
+  CollectEmptyProfiles(
       CallStackProfileParams(CallStackProfileParams::GPU_PROCESS,
                              CallStackProfileParams::GPU_MAIN_THREAD,
                              CallStackProfileParams::THREAD_HUNG,
                              CallStackProfileParams::PRESERVE_ORDER),
-      { base::StackSamplingProfiler::CallStackProfile() });
+      1);
   base::RunLoop().RunUntilIdle();
   EXPECT_EQ(0u, profiles().size());
   ASSERT_EQ(1u, receiver_impl_->profiles.size());
   EXPECT_EQ(CallStackProfileParams::GPU_PROCESS,
             receiver_impl_->profiles[0].params.process);
   EXPECT_EQ(CallStackProfileParams::GPU_MAIN_THREAD,
             receiver_impl_->profiles[0].params.thread);
   EXPECT_EQ(CallStackProfileParams::THREAD_HUNG,
             receiver_impl_->profiles[0].params.trigger);
   EXPECT_EQ(CallStackProfileParams::PRESERVE_ORDER,
             receiver_impl_->profiles[0].params.ordering_spec);
   EXPECT_GE(base::TimeDelta::FromMilliseconds(10),
             (base::TimeTicks::Now() -
              receiver_impl_->profiles[0].start_timestamp));
   EXPECT_EQ(1u, receiver_impl_->profiles[0].profiles.size());
 }
 
 TEST_F(ChildCallStackProfileCollectorTest, InterfaceNotProvided) {
   EXPECT_EQ(0u, profiles().size());
 
   // Add profiles before providing a null interface.
-  CollectProfiles(
+  CollectEmptyProfiles(
       CallStackProfileParams(CallStackProfileParams::BROWSER_PROCESS,
                              CallStackProfileParams::UI_THREAD,
                              CallStackProfileParams::JANKY_TASK,
                              CallStackProfileParams::PRESERVE_ORDER),
-      { base::StackSamplingProfiler::CallStackProfile(),
-            base::StackSamplingProfiler::CallStackProfile() });
+      2);
   ASSERT_EQ(1u, profiles().size());
   EXPECT_EQ(CallStackProfileParams::BROWSER_PROCESS,
             profiles()[0].params.process);
   EXPECT_EQ(CallStackProfileParams::UI_THREAD, profiles()[0].params.thread);
   EXPECT_EQ(CallStackProfileParams::JANKY_TASK, profiles()[0].params.trigger);
   EXPECT_EQ(CallStackProfileParams::PRESERVE_ORDER,
             profiles()[0].params.ordering_spec);
   EXPECT_GE(base::TimeDelta::FromMilliseconds(10),
             base::TimeTicks::Now() - profiles()[0].start_timestamp);
   EXPECT_EQ(2u, profiles()[0].profiles.size());
 
   // Set the null interface. The profiles should be flushed.
   child_collector_.SetParentProfileCollector(
       mojom::CallStackProfileCollectorPtr());
   base::RunLoop().RunUntilIdle();
   EXPECT_EQ(0u, profiles().size());
 
   // Add profiles after providing a null interface. They should also be flushed.
-  CollectProfiles(
+  CollectEmptyProfiles(
       CallStackProfileParams(CallStackProfileParams::GPU_PROCESS,
                              CallStackProfileParams::GPU_MAIN_THREAD,
                              CallStackProfileParams::THREAD_HUNG,
                              CallStackProfileParams::PRESERVE_ORDER),
-      { base::StackSamplingProfiler::CallStackProfile() });
+      1);
   EXPECT_EQ(0u, profiles().size());
 }
 
 }  // namespace metrics