Reland "Throttle resource message requests during user interaction"

content/renderer/resource_dispatch_throttler_unittest.cc

Index: content/renderer/resource_dispatch_throttler_unittest.cc
diff --git a/content/renderer/resource_dispatch_throttler_unittest.cc b/content/renderer/resource_dispatch_throttler_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..12478f7469824b38c15e4145b357ea3c2b2b3e63
--- /dev/null
+++ b/content/renderer/resource_dispatch_throttler_unittest.cc
@@ -0,0 +1,345 @@
+// 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 "content/renderer/resource_dispatch_throttler.h"
+
+#include "base/memory/scoped_vector.h"
+#include "content/common/resource_messages.h"
+#include "content/test/fake_renderer_scheduler.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace content {
+namespace {
+
+const uint32 kRequestsPerFlush = 4;
+const double kFlushPeriodSeconds = 1.f / 60;
+const int kRoutingId = 1;
+
+typedef ScopedVector<IPC::Message> ScopedMessages;
+
+class SenderSink : public IPC::Sender {
+ public:
+  SenderSink(ScopedMessages* sent_messages) : sent_messages_(sent_messages) {}
+
+  // IPC::Sender implementation:
+  bool Send(IPC::Message* msg) override {
+    sent_messages_->push_back(msg);
+    return true;
+  }
+
+ private:
+  ScopedMessages* sent_messages_;
+};
+
+}  // namespace
+
+class ResourceDispatchThrottlerTest : public testing::Test,
+                                      public FakeRendererScheduler,
+                                      public ResourceDispatchThrottler {
+ public:
+  ResourceDispatchThrottlerTest()
+      : ResourceDispatchThrottler(
+            &sender_sink_,
+            this,
+            base::TimeDelta::FromSecondsD(kFlushPeriodSeconds),
+            kRequestsPerFlush),
+        sender_sink_(&sent_messages_),
+        flush_scheduled_(false),
+        anticipate_(false),
+        last_request_id_(0) {}
+  ~ResourceDispatchThrottlerTest() override {}
+
+  // RendererScheduler implementation:
+  bool ShouldAnticipateHighPriorityWork() override { return anticipate_; }
+
+ protected:
+  base::TimeTicks Now() const override { return now_; }
+
+  void ScheduleFlush() override { flush_scheduled_ = true; }
+
+  void SetShouldAnticipateHighPriorityWork(bool anticipate) {
+    anticipate_ = anticipate;
+  }
+
+  void Advance(base::TimeDelta delta) { now_ += delta; }
+
+  bool RunScheduledFlush() {
+    if (!flush_scheduled_)
+      return false;
+
+    flush_scheduled_ = false;
+    Flush();
+    return true;
+  }
+
+  bool RequestResource() {
+    ResourceHostMsg_Request request;
+    request.download_to_file = true;
+    return Send(new ResourceHostMsg_RequestResource(
+        kRoutingId, ++last_request_id_, request));
+  }
+
+  void RequestResourcesUntilThrottled() {
+    SetShouldAnticipateHighPriorityWork(true);
+    GetAndResetSentMessageCount();
+    for (RequestResource(); GetAndResetSentMessageCount(); RequestResource()) {
+    }
+  }
+
+  bool UpdateRequestPriority(int request_id, net::RequestPriority priority) {
+    return Send(new ResourceHostMsg_DidChangePriority(request_id, priority, 0));
+  }
+
+  bool ReleaseDownloadedFile(int request_id) {
+    return Send(new ResourceHostMsg_ReleaseDownloadedFile(request_id));
+  }
+
+  bool CancelRequest(int request_id) {
+    return Send(new ResourceHostMsg_CancelRequest(request_id));
+  }
+
+  bool RequestResourceSync() {
+    SyncLoadResult result;
+    return Send(new ResourceHostMsg_SyncLoad(
+        kRoutingId, ++last_request_id_, ResourceHostMsg_Request(), &result));
+  }
+
+  size_t GetAndResetSentMessageCount() {
+    size_t sent_message_count = sent_messages_.size();
+    sent_messages_.clear();
+    return sent_message_count;
+  }
+
+  const IPC::Message* LastSentMessage() const {
+    return sent_messages_.empty() ? nullptr : sent_messages_.back();
+  }
+
+  int LastSentRequestId() const {
+    const IPC::Message* msg = LastSentMessage();
+    if (!msg)
+      return -1;
+
+    int routing_id = -1;
+    int request_id = -1;
+    PickleIterator iter(*msg);
+    CHECK(IPC::ReadParam(msg, &iter, &routing_id));
+    CHECK(IPC::ReadParam(msg, &iter, &request_id));
+    return request_id;
+  }
+
+  int last_request_id() const { return last_request_id_; }
+
+  ScopedMessages sent_messages_;
+
+ private:
+  SenderSink sender_sink_;
+  base::MessageLoopForUI message_loop_;
+  base::TimeTicks now_;
+  bool flush_scheduled_;
+  bool anticipate_;
+  int last_request_id_;
+
+  DISALLOW_COPY_AND_ASSIGN(ResourceDispatchThrottlerTest);
+};
+
+TEST_F(ResourceDispatchThrottlerTest, NotThrottledByDefault) {
+  SetShouldAnticipateHighPriorityWork(false);
+  for (size_t i = 0; i < kRequestsPerFlush * 2; ++i) {
+    RequestResource();
+    EXPECT_EQ(i + 1, sent_messages_.size());
+  }
+}
+
+TEST_F(ResourceDispatchThrottlerTest, NotThrottledIfSendLimitNotReached) {
+  SetShouldAnticipateHighPriorityWork(true);
+  for (size_t i = 0; i < kRequestsPerFlush; ++i) {
+    RequestResource();
+    EXPECT_EQ(i + 1, sent_messages_.size());
+  }
+}
+
+TEST_F(ResourceDispatchThrottlerTest, ThrottledWhenHighPriorityWork) {
+  SetShouldAnticipateHighPriorityWork(true);
+  for (size_t i = 0; i < kRequestsPerFlush; ++i)
+    RequestResource();
+  ASSERT_EQ(kRequestsPerFlush, GetAndResetSentMessageCount());
+
+  RequestResource();
+  EXPECT_EQ(0U, sent_messages_.size());
+
+  EXPECT_TRUE(RunScheduledFlush());
+  EXPECT_EQ(1U, sent_messages_.size());
+}
+
+TEST_F(ResourceDispatchThrottlerTest,
+       ThrottledWhenDeferredMessageQueueNonEmpty) {
+  SetShouldAnticipateHighPriorityWork(true);
+  for (size_t i = 0; i < kRequestsPerFlush; ++i)
+    RequestResource();
+  ASSERT_EQ(kRequestsPerFlush, GetAndResetSentMessageCount());
+
+  RequestResource();
+  EXPECT_EQ(0U, sent_messages_.size());
+  SetShouldAnticipateHighPriorityWork(false);
+  RequestResource();
+  EXPECT_EQ(0U, sent_messages_.size());
+
+  EXPECT_TRUE(RunScheduledFlush());
+  EXPECT_EQ(2U, sent_messages_.size());
+}
+
+TEST_F(ResourceDispatchThrottlerTest, NotThrottledIfSufficientTimePassed) {
+  SetShouldAnticipateHighPriorityWork(true);
+
+  for (size_t i = 0; i < kRequestsPerFlush * 2; ++i) {
+    Advance(base::TimeDelta::FromSecondsD(kFlushPeriodSeconds * 2));
+    RequestResource();
+    EXPECT_EQ(1U, GetAndResetSentMessageCount());
+    EXPECT_FALSE(RunScheduledFlush());
+  }
+}
+
+TEST_F(ResourceDispatchThrottlerTest, NotThrottledIfUnthrottledMessageType) {
+  SetShouldAnticipateHighPriorityWork(true);
+
+  RequestResourceSync();
+  EXPECT_EQ(1U, GetAndResetSentMessageCount());
+
+  // Saturate the queue.
+  for (size_t i = 0; i < kRequestsPerFlush * 2; ++i)
+    RequestResource();
+  ASSERT_EQ(kRequestsPerFlush, GetAndResetSentMessageCount());
+
+  // Unthrottled message types should pass through untouched.
+  RequestResourceSync();
+  EXPECT_EQ(1U, GetAndResetSentMessageCount());
+  RequestResourceSync();
+  EXPECT_EQ(1U, GetAndResetSentMessageCount());
+
+  // Deferred messages should flush as usual.
+  EXPECT_TRUE(RunScheduledFlush());
+  EXPECT_EQ(kRequestsPerFlush, GetAndResetSentMessageCount());
+}
+
+TEST_F(ResourceDispatchThrottlerTest, MultipleFlushes) {
+  SetShouldAnticipateHighPriorityWork(true);
+  for (size_t i = 0; i < kRequestsPerFlush * 4; ++i)
+    RequestResource();
+  ASSERT_EQ(kRequestsPerFlush, GetAndResetSentMessageCount());
+
+  for (size_t i = 0; i < 3; ++i) {
+    EXPECT_TRUE(RunScheduledFlush());
+    EXPECT_EQ(kRequestsPerFlush, GetAndResetSentMessageCount()) << i;
+  }
+
+  EXPECT_FALSE(RunScheduledFlush());
+  EXPECT_EQ(0U, sent_messages_.size());
+}
+
+TEST_F(ResourceDispatchThrottlerTest, MultipleFlushesWhileReceiving) {
+  SetShouldAnticipateHighPriorityWork(true);
+  for (size_t i = 0; i < kRequestsPerFlush * 4; ++i)
+    RequestResource();
+  ASSERT_EQ(kRequestsPerFlush, GetAndResetSentMessageCount());
+
+  for (size_t i = 0; i < 3; ++i) {
+    EXPECT_TRUE(RunScheduledFlush());
+    EXPECT_EQ(kRequestsPerFlush, GetAndResetSentMessageCount()) << i;
+    for (size_t j = 0; j < kRequestsPerFlush; ++j)
+      RequestResource();
+    EXPECT_EQ(0U, sent_messages_.size()) << i;
+  }
+
+  for (size_t i = 0; i < 3; ++i) {
+    EXPECT_TRUE(RunScheduledFlush());
+    EXPECT_EQ(kRequestsPerFlush, GetAndResetSentMessageCount());
+  }
+
+  EXPECT_FALSE(RunScheduledFlush());
+  EXPECT_EQ(0U, sent_messages_.size());
+}
+
+TEST_F(ResourceDispatchThrottlerTest, CancelRequest) {
+  RequestResource();
+  ASSERT_EQ(1U, GetAndResetSentMessageCount());
+
+  // Cancel messages for an unthrottled request will be forwarded immediately.
+  CancelRequest(last_request_id());
+  ASSERT_EQ(1U, sent_messages_.size());
+  EXPECT_EQ(ResourceHostMsg_CancelRequest::ID, LastSentMessage()->type());
+
+  RequestResourcesUntilThrottled();
+
+  // The cancelled request should never be sent.
+  CancelRequest(last_request_id());
+  ASSERT_EQ(0U, sent_messages_.size());
+  EXPECT_TRUE(RunScheduledFlush());
+  EXPECT_EQ(0U, sent_messages_.size());
+}
+
+TEST_F(ResourceDispatchThrottlerTest, CancelRequestOutOfOrder) {
+  SetShouldAnticipateHighPriorityWork(true);
+  for (size_t i = 0; i < kRequestsPerFlush; ++i)
+    RequestResource();
+  ASSERT_EQ(kRequestsPerFlush, GetAndResetSentMessageCount());
+
+  for (size_t i = 0; i < kRequestsPerFlush; ++i)
+    RequestResource();
+  ASSERT_EQ(0U, sent_messages_.size());
+
+  // Cancel the first and last throttled request, ensuring they're not flushed.
+  CancelRequest(last_request_id());
+  CancelRequest(last_request_id() - 2);
+  EXPECT_TRUE(RunScheduledFlush());
+  ASSERT_EQ(kRequestsPerFlush - 2, sent_messages_.size());
+  EXPECT_EQ(LastSentRequestId(), last_request_id() - 1);
+}
+
+TEST_F(ResourceDispatchThrottlerTest, PriorityUpdate) {
+  RequestResource();
+  ASSERT_EQ(1U, GetAndResetSentMessageCount());
+
+  // Priority updates for an unthrottled request will be forwarded immediately.
+  UpdateRequestPriority(last_request_id(), net::HIGHEST);
+  ASSERT_EQ(1U, sent_messages_.size());
+  EXPECT_EQ(ResourceHostMsg_DidChangePriority::ID, LastSentMessage()->type());
+
+  RequestResourcesUntilThrottled();
+
+  // The updated priority should be reflected in the flushed message.
+  UpdateRequestPriority(last_request_id(), net::HIGHEST);
+  ASSERT_EQ(0U, sent_messages_.size());
+  EXPECT_TRUE(RunScheduledFlush());
+  ASSERT_EQ(1U, sent_messages_.size());
+  ResourceHostMsg_RequestResource::Param request_params;
+  ASSERT_TRUE(ResourceHostMsg_RequestResource::Read(LastSentMessage(),
+                                                    &request_params));
+  EXPECT_EQ(net::HIGHEST, get<2>(request_params).priority);
+}
+
+TEST_F(ResourceDispatchThrottlerTest, ReleaseDownloadFileUpdate) {
+  RequestResource();
+  ASSERT_EQ(1U, GetAndResetSentMessageCount());
+
+  // Download request updates for an unthrottled request will be
+  // immediately.
+  ReleaseDownloadedFile(last_request_id());
+  ASSERT_EQ(1U, sent_messages_.size());
+  EXPECT_EQ(ResourceHostMsg_ReleaseDownloadedFile::ID,
+            LastSentMessage()->type());
+
+  RequestResourcesUntilThrottled();
+
+  // The download request update should be reflected in the flushed message.
+  ReleaseDownloadedFile(last_request_id());
+  ASSERT_EQ(0U, sent_messages_.size());
+  EXPECT_TRUE(RunScheduledFlush());
+  ASSERT_EQ(1U, sent_messages_.size());
+  ResourceHostMsg_RequestResource::Param request_params;
+  ASSERT_TRUE(ResourceHostMsg_RequestResource::Read(LastSentMessage(),
+                                                    &request_params));
+  EXPECT_FALSE(get<2>(request_params).download_to_file);
+}
+
+}  // namespace content