arc: Stop waiting for crash reporter on UI thread

components/arc/crash_collector/arc_crash_collector_bridge.h

 // 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.
 
 #ifndef COMPONENTS_ARC_CRASH_COLLECTOR_ARC_CRASH_COLLECTOR_BRIDGE_H_
 #define COMPONENTS_ARC_CRASH_COLLECTOR_ARC_CRASH_COLLECTOR_BRIDGE_H_
 
 #include <string>
 
 #include "base/macros.h"
+#include "base/memory/ref_counted.h"
 #include "components/arc/arc_bridge_service.h"
 #include "components/arc/arc_service.h"
 #include "components/arc/instance_holder.h"
 #include "mojo/public/cpp/bindings/binding.h"
 
+namespace base {
+class TaskRunner;
+}
+
 namespace arc {
 
 // Relays dumps for non-native ARC crashes to the crash reporter in Chrome OS.
 class ArcCrashCollectorBridge
     : public ArcService,
       public InstanceHolder<mojom::CrashCollectorInstance>::Observer,
       public mojom::CrashCollectorHost {
  public:
-  explicit ArcCrashCollectorBridge(ArcBridgeService* bridge);
+  ArcCrashCollectorBridge(ArcBridgeService* bridge,
+                          scoped_refptr<base::TaskRunner> blocking_task_runner);
   ~ArcCrashCollectorBridge() override;
 
   // InstanceHolder<mojom::CrashCollectorInstance>::Observer overrides.
   void OnInstanceReady() override;
 
   // mojom::CrashCollectorHost overrides.
   void DumpCrash(const mojo::String& type, mojo::ScopedHandle pipe) override;
 
   void SetBuildProperties(const mojo::String& device,
                           const mojo::String& board,
                           const mojo::String& cpu_abi) override;
 
  private:
+  scoped_refptr<base::TaskRunner> blocking_task_runner_;
+
   mojo::Binding<mojom::CrashCollectorHost> binding_;
 
   std::string device_;
   std::string board_;
   std::string cpu_abi_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcCrashCollectorBridge);
 };
 
 }  // namespace arc
 
 #endif  // COMPONENTS_ARC_CRASH_COLLECTOR_ARC_CRASH_COLLECTOR_BRIDGE_H_