Incorporate BlobChannel into Blimp image encode/decode pipeline.

blimp/client/feature/compositor/blimp_compositor_unittest.cc

Index: blimp/client/feature/compositor/blimp_compositor_unittest.cc
diff --git a/blimp/client/feature/compositor/blimp_compositor_unittest.cc b/blimp/client/feature/compositor/blimp_compositor_unittest.cc
index 27655572e8bb6eee81fbc469d7f64c3ac0571759..c3a517886223bf8f2f13d9184370f9b459292535 100644
--- a/blimp/client/feature/compositor/blimp_compositor_unittest.cc
+++ b/blimp/client/feature/compositor/blimp_compositor_unittest.cc
@@ -33,7 +33,7 @@ class MockBlimpCompositorClient : public BlimpCompositorClient {
     return &gpu_memory_buffer_manager_;
   }
   cc::ImageSerializationProcessor* GetImageSerializationProcessor() override {
-    return &image_serialization_processor_;
+    return ClientImageSerializationProcessor::GetInstance();
   }
   void DidCompleteSwapBuffers() override {}
   void DidCommitAndDrawFrame() override {}
@@ -56,7 +56,6 @@ class MockBlimpCompositorClient : public BlimpCompositorClient {
   base::Thread compositor_thread_;
   BlimpTaskGraphRunner task_graph_runner_;
   BlimpGpuMemoryBufferManager gpu_memory_buffer_manager_;
-  ClientImageSerializationProcessor image_serialization_processor_;
 };
 
 class BlimpCompositorForTesting : public BlimpCompositor {