[Large Icon Service] Move icon resizing into worker thread.

components/favicon/core/large_icon_service_unittest.cc

Index: components/favicon/core/large_icon_service_unittest.cc
diff --git a/components/favicon/core/large_icon_service_unittest.cc b/components/favicon/core/large_icon_service_unittest.cc
index 48422ab55a39552a545d4d087af8528a9001bcfd..826eaf997dab9758ca5b4ab467065cea47be9547 100644
--- a/components/favicon/core/large_icon_service_unittest.cc
+++ b/components/favicon/core/large_icon_service_unittest.cc
@@ -96,6 +96,11 @@ class TestLargeIconService : public LargeIconService {
   ~TestLargeIconService() override {
   }
 
+  // Using the current thread's task runner for testing.
+  scoped_refptr<base::TaskRunner> GetBackgroundTaskRunner() override {
+    return base::MessageLoop::current()->task_runner();
+  }
+
  private:
   DISALLOW_COPY_AND_ASSIGN(TestLargeIconService);
 };
@@ -152,7 +157,6 @@ class LargeIconServiceTest : public testing::Test {
 };
 
 TEST_F(LargeIconServiceTest, SameSize) {
-
   mock_favicon_service_->InjectResult(CreateTestBitmap(24, 24, kTestColor));
   expected_bitmap_ = CreateTestBitmap(24, 24, kTestColor);
   large_icon_service_->GetLargeIconOrFallbackStyle(