Add favicon integration tests for FaviconDriverImpl

components/history/core/browser/history_service.cc

Index: components/history/core/browser/history_service.cc
diff --git a/components/history/core/browser/history_service.cc b/components/history/core/browser/history_service.cc
index b154b3237e19b1373d1c0ba522aefc8229a51861..bb3339dcd5bcb3babf9b512bf1991d64ce30be90 100644
--- a/components/history/core/browser/history_service.cc
+++ b/components/history/core/browser/history_service.cc
@@ -318,6 +318,13 @@ base::CancelableTaskTracker::TaskId HistoryService::ScheduleDBTask(
   return task_id;
 }
 
+bool HistoryService::InitForTest(
+    const HistoryDatabaseParams& history_database_params,
+    scoped_refptr<base::SequencedTaskRunner> task_runner) {
+  return InitWithTaskRunner(/*no_db=*/false, history_database_params,
+                            task_runner);
+}
+
 void HistoryService::FlushForTest(const base::Closure& flushed) {
   backend_task_runner_->PostTaskAndReply(FROM_HERE,
                                          base::Bind(&base::DoNothing), flushed);
@@ -870,8 +877,6 @@ bool HistoryService::Init(
     const HistoryDatabaseParams& history_database_params) {
   TRACE_EVENT0("browser,startup", "HistoryService::Init")
   SCOPED_UMA_HISTOGRAM_TIMER("History.HistoryServiceInitTime");
-  DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(!backend_task_runner_);
 
   if (thread_) {
     base::Thread::Options options;
@@ -880,15 +885,29 @@ bool HistoryService::Init(
       Cleanup();
       return false;
     }
-    backend_task_runner_ = thread_->task_runner();
+    return InitWithTaskRunner(no_db, history_database_params,
+                              thread_->task_runner());
   } else {
-    backend_task_runner_ = base::CreateSequencedTaskRunnerWithTraits(
-        base::TaskTraits()
-            .WithPriority(base::TaskPriority::USER_BLOCKING)
-            .WithShutdownBehavior(base::TaskShutdownBehavior::BLOCK_SHUTDOWN)
-            .MayBlock()
-            .WithBaseSyncPrimitives());
+    return InitWithTaskRunner(
+        no_db, history_database_params,
+        base::CreateSequencedTaskRunnerWithTraits(
+            base::TaskTraits()
+                .WithPriority(base::TaskPriority::USER_BLOCKING)
+                .WithShutdownBehavior(
+                    base::TaskShutdownBehavior::BLOCK_SHUTDOWN)
+                .MayBlock()
+                .WithBaseSyncPrimitives()));
   }
+}
+
+bool HistoryService::InitWithTaskRunner(
+    bool no_db,
+    const HistoryDatabaseParams& history_database_params,
+    scoped_refptr<base::SequencedTaskRunner> task_runner) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(!backend_task_runner_);
+
+  backend_task_runner_ = task_runner;
 
   // Create the history backend.
   scoped_refptr<HistoryBackend> backend(new HistoryBackend(