arc: Stop waiting for crash reporter on UI thread

components/arc/crash_collector/arc_crash_collector_bridge.h

Index: components/arc/crash_collector/arc_crash_collector_bridge.h
diff --git a/components/arc/crash_collector/arc_crash_collector_bridge.h b/components/arc/crash_collector/arc_crash_collector_bridge.h
index cb234759a8419f3563a86883122c8f299effeb34..0b7ec562f0c2ea6d666faa6375d8fda0beae05f3 100644
--- a/components/arc/crash_collector/arc_crash_collector_bridge.h
+++ b/components/arc/crash_collector/arc_crash_collector_bridge.h
@@ -8,11 +8,16 @@
 #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.
@@ -21,7 +26,8 @@ class ArcCrashCollectorBridge
       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.
@@ -35,6 +41,8 @@ class ArcCrashCollectorBridge
                           const mojo::String& cpu_abi) override;
 
  private:
+  scoped_refptr<base::TaskRunner> blocking_task_runner_;
+
   mojo::Binding<mojom::CrashCollectorHost> binding_;
 
   std::string device_;