Fix image_decoder unit tests

services/image_decoder/image_decoder_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 <memory>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/lazy_instance.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 63 matching lines @@
 #if defined(V8_USE_EXTERNAL_STARTUP_DATA)
     gin::V8Initializer::LoadV8Snapshot();
     gin::V8Initializer::LoadV8Natives();
 #endif
 
     blink::initialize(this);
   }
 
   ~BlinkInitializer() override {}
 
+  blink::WebThread* currentThread() override { return main_thread_.get(); }
+
  private:
   std::unique_ptr<blink::scheduler::WebThreadImplForUtilityThread> main_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(BlinkInitializer);
 };
 
 base::LazyInstance<BlinkInitializer>::Leaky g_blink_initializer =
     LAZY_INSTANCE_INITIALIZER;
 
 class ImageDecoderImplTest : public testing::Test {
@@ skipping 58 matching lines @@
   const char kRandomData[] = "u gycfy7xdjkhfgui bdui ";
   std::vector<unsigned char> jpg(kRandomData,
                                  kRandomData + sizeof(kRandomData));
 
   Request request(decoder());
   request.DecodeImage(jpg, false);
   EXPECT_TRUE(request.bitmap().isNull());
 }
 
 }  // namespace image_decoder