Revert of Replace system IO calls in chromecast/crash with Chrome utilities.

chromecast/crash/linux/dummy_minidump_generator.h

 // Copyright 2015 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 CHROMECAST_CRASH_LINUX_DUMMY_MINIDUMP_GENERATOR_H_
 #define CHROMECAST_CRASH_LINUX_DUMMY_MINIDUMP_GENERATOR_H_
 
 #include <string>
 
 #include "base/macros.h"
 #include "chromecast/crash/linux/minidump_generator.h"
 
 namespace chromecast {
 
 class DummyMinidumpGenerator : public MinidumpGenerator {
  public:
   // A dummy minidump generator to move an existing minidump into
   // crash_uploader's monitoring path ($HOME/minidumps). The path is monitored
   // with file lock-control, so that third process should not write to it
   // directly.
   explicit DummyMinidumpGenerator(const std::string& existing_minidump_path);
 
   // MinidumpGenerator implementation:
-  // Moves the minidump located at |existing_minidump_path_| to |minidump_path|.
-  // Returns true if successful, false otherwise. Note that this function MUST
-  // be called on a thread without IO restrictions, or it will fail fatally.
   bool Generate(const std::string& minidump_path) override;
 
+  // Provide access to internal utility for testing.
+  bool CopyAndDeleteForTest(const std::string& dest_path) {
+    return CopyAndDelete(dest_path);
+  }
+
  private:
+  // Copies the contents of the file at |existing_minidump_path_| to the file at
+  // |dest_path|. If the copy operation succeeds, delete the file at
+  // |existing_minidump_path_|. Returns false if |existing_minidump_path_| can't
+  // be opened, or if the copy operation fails. Ideally, we would use Chrome
+  // utilities for a task like this, but we must ensure that this operation can
+  // occur on any thread (regardless of IO restrictions).
+  bool CopyAndDelete(const std::string& dest_path);
+
   const std::string existing_minidump_path_;
 
   DISALLOW_COPY_AND_ASSIGN(DummyMinidumpGenerator);
 };
 
 }  // namespace chromecast
 
 #endif  // CHROMECAST_CRASH_LINUX_DUMMY_MINIDUMP_GENERATOR_H_