[NTP Tiles] Avoid duplicate requests from IconCacherImpl

components/ntp_tiles/icon_cacher_impl_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/ntp_tiles/icon_cacher_impl.h"
 
 #include <set>
 #include <utility>
 
 #include "base/files/scoped_temp_dir.h"
@@ skipping 358 matching lines @@
   default_loop.Run();  // Wait for the default image.
   EXPECT_THAT(GetCachedIconFor(site_.url, favicon_base::TOUCH_ICON).Size(),
               Eq(gfx::Size(64, 64)));  // Compares dimensions, not objects.
 
   // Let the fetcher continue and wait for the second call of the callback.
   fetch_loop.Run();  // Wait for the updated image.
   EXPECT_THAT(GetCachedIconFor(site_.url, favicon_base::TOUCH_ICON).Size(),
               Eq(gfx::Size(128, 128)));  // Compares dimensions, not objects.
 }
 
+TEST_F(IconCacherTestPopularSites, LargeNotCachedAndFetchPerformedOnlyOnce) {
+  base::MockCallback<base::Closure> done;
+  base::RunLoop loop;
+  {
+    InSequence s;
+    // Image fetcher is used only once.
+    EXPECT_CALL(*image_fetcher_,
+                SetDataUseServiceName(
+                    data_use_measurement::DataUseUserData::NTP_TILES));
+    EXPECT_CALL(*image_fetcher_, SetDesiredImageFrameSize(gfx::Size(128, 128)));
+    EXPECT_CALL(*image_fetcher_,
+                StartOrQueueNetworkRequest(_, site_.large_icon_url, _))
+        .WillOnce(PassFetch(128, 128));
+    // Success will be notified to both requests.
+    EXPECT_CALL(done, Run()).WillOnce(Return()).WillOnce(Quit(&loop));
+  }
+
+  IconCacherImpl cacher(&favicon_service_, nullptr, std::move(image_fetcher_));
+  cacher.StartFetchPopularSites(site_, done.Get(), done.Get());
+  cacher.StartFetchPopularSites(site_, done.Get(), done.Get());
+  loop.Run();
+  EXPECT_FALSE(IconIsCachedFor(site_.url, favicon_base::FAVICON));
+  EXPECT_TRUE(IconIsCachedFor(site_.url, favicon_base::TOUCH_ICON));
+}
+
 class IconCacherTestMostLikely : public IconCacherTestBase {
  protected:
   IconCacherTestMostLikely()
       : large_icon_service_background_task_runner_(
             new base::TestSimpleTaskRunner()),
         fetcher_for_large_icon_service_(
             base::MakeUnique<::testing::StrictMock<MockImageFetcher>>()),
         fetcher_for_icon_cacher_(
             base::MakeUnique<::testing::StrictMock<MockImageFetcher>>()) {
     // Expect uninteresting calls here, |fetcher_for_icon_cacher_| is not
@@ skipping 116 matching lines @@
   // queue in order to finish the work.
   WaitForHistoryThreadTasksToFinish();
   large_icon_service_background_task_runner_->RunUntilIdle();
   WaitForMainThreadTasksToFinish();
 
   // Even though the callbacks are not called, the icon gets written out.
   EXPECT_FALSE(IconIsCachedFor(page_url, favicon_base::FAVICON));
   EXPECT_TRUE(IconIsCachedFor(page_url, favicon_base::TOUCH_ICON));
 }
 
+TEST_F(IconCacherTestMostLikely, NotCachedAndFetchPerformedOnlyOnce) {
+  GURL page_url("http://www.site.com");
+
+  base::MockCallback<base::Closure> done;
+  base::RunLoop loop;
+  {
+    InSequence s;
+    // Image fetcher is used only once.
+    EXPECT_CALL(*fetcher_for_large_icon_service_,
+                SetDataUseServiceName(
+                    data_use_measurement::DataUseUserData::LARGE_ICON_SERVICE));
+    EXPECT_CALL(*fetcher_for_large_icon_service_,
+                StartOrQueueNetworkRequest(_, _, _))
+        .WillOnce(PassFetch(128, 128));
+    // Success will be notified to both requests.
+    EXPECT_CALL(done, Run()).WillOnce(Return()).WillOnce(Quit(&loop));
+  }
+
+  favicon::LargeIconService large_icon_service(
+      &favicon_service_, large_icon_service_background_task_runner_,
+      std::move(fetcher_for_large_icon_service_));
+  IconCacherImpl cacher(&favicon_service_, &large_icon_service,
+                        std::move(fetcher_for_icon_cacher_));
+
+  cacher.StartFetchMostLikely(page_url, done.Get());
+  cacher.StartFetchMostLikely(page_url, done.Get());
+  // Both these task runners need to be flushed in order to get |done| called by
+  // running the main loop.
+  WaitForHistoryThreadTasksToFinish();
+  large_icon_service_background_task_runner_->RunUntilIdle();
+
+  loop.Run();
+  EXPECT_FALSE(IconIsCachedFor(page_url, favicon_base::FAVICON));
+  EXPECT_TRUE(IconIsCachedFor(page_url, favicon_base::TOUCH_ICON));
+}
+
 }  // namespace
 }  // namespace ntp_tiles