Don't start a second pre-render if one is in progress.

components/offline_pages/background/request_coordinator_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/offline_pages/background/request_coordinator.h"
 
 #include <memory>
 #include <utility>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/location.h"
+#include "base/logging.h"
 #include "base/test/test_simple_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "components/offline_pages/background/device_conditions.h"
 #include "components/offline_pages/background/offliner.h"
 #include "components/offline_pages/background/offliner_factory.h"
 #include "components/offline_pages/background/offliner_policy.h"
 #include "components/offline_pages/background/request_queue.h"
 #include "components/offline_pages/background/request_queue_in_memory_store.h"
 #include "components/offline_pages/background/save_page_request.h"
 #include "components/offline_pages/background/scheduler.h"
@@ skipping 62 matching lines @@
   ~RequestCoordinatorTest() override;
 
   void SetUp() override;
 
   void PumpLoop();
 
   RequestCoordinator* coordinator() {
     return coordinator_.get();
   }
 
+  bool request_in_progress() {
+    return coordinator_->is_busy();
+  }
+
+  void SendRequestToOffliner(SavePageRequest& request) {
+    coordinator_->SendRequestToOffliner(request);
+  }
+
   // Empty callback function
   void EmptyCallbackFunction(bool result) {
   }
 
   // Callback for Add requests
   void AddRequestDone(RequestQueue::AddRequestResult result,
                       const SavePageRequest& request);
 
   // Callback for getting requests.
   void GetRequestsDone(RequestQueue::GetRequestsResult result,
@@ skipping 63 matching lines @@
 TEST_F(RequestCoordinatorTest, StartProcessingWithNoRequests) {
   DeviceConditions device_conditions(false, 75,
                                      net::NetworkChangeNotifier::CONNECTION_3G);
   base::Callback<void(bool)> callback =
       base::Bind(
           &RequestCoordinatorTest::EmptyCallbackFunction,
           base::Unretained(this));
   EXPECT_TRUE(coordinator()->StartProcessing(device_conditions, callback));
 }
 
+TEST_F(RequestCoordinatorTest, StartProcessingWithRequestInProgress) {
+  // Build a request.
+  offline_pages::SavePageRequest request(
+      kRequestId, kUrl, kClientId, base::Time::Now());
+  // Sending the request to the offliner should make it busy.
+  SendRequestToOffliner(request);
+  EXPECT_TRUE(request_in_progress());

[dougarnett, 2016/06/22 17:25:47]

suggest using the is_busy() naming for the test class as well - to be consistent

[Pete Williamson, 2016/06/22 22:32:27]

Done.

+  // Now trying to start processing on another request should return false.
+  DeviceConditions device_conditions(false, 75,
+                                     net::NetworkChangeNotifier::CONNECTION_3G);
+  base::Callback<void(bool)> callback =
+      base::Bind(
+          &RequestCoordinatorTest::EmptyCallbackFunction,
+          base::Unretained(this));
+  EXPECT_FALSE(coordinator()->StartProcessing(device_conditions, callback));
+}
+
 TEST_F(RequestCoordinatorTest, SavePageLater) {
   EXPECT_TRUE(coordinator()->SavePageLater(kUrl, kClientId));
 
   // Expect that a request got placed on the queue.
   coordinator()->queue()->GetRequests(
       base::Bind(&RequestCoordinatorTest::GetRequestsDone,
                  base::Unretained(this)));
 
   // Wait for callbacks to finish, both request queue and offliner.
   PumpLoop();
@@ skipping 70 matching lines @@
       base::Bind(&RequestCoordinatorTest::GetRequestsDone,
                  base::Unretained(this)));
   PumpLoop();
 
   // Still one request in the queue.
   EXPECT_EQ(1UL, last_requests().size());
   // TODO(dougarnett): Verify retry count gets incremented.
 }
 
 }  // namespace offline_pages