debugd: Fix coding style and cpplint issues.

BUG=chromium:385849
TEST=`FEATURES=test emerge-$BOARD platform2`
TEST=`cpplint.py --root=src --filter=-build/include src/{*.h,*.cc,*/*.cc}`

Change-Id: Ia2475d6ee287dc727c3b2ffe139e9cc8bfe2e2e5
Reviewed-on: https://chromium-review.googlesource.com/204391
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Tested-by: Ben Chan <benchan@chromium.org>
Commit-Queue: Ben Chan <benchan@chromium.org>
diff --git a/debugd/src/example_tool.h b/debugd/src/example_tool.h
index 0b3c148..1232408 100644
--- a/debugd/src/example_tool.h
+++ b/debugd/src/example_tool.h
@@ -4,8 +4,8 @@
 //
 // This is an example of a tool. See </src/example_tool.cc>.
 
-#ifndef EXAMPLE_TOOL_H
-#define EXAMPLE_TOOL_H
+#ifndef EXAMPLE_TOOL_H_
+#define EXAMPLE_TOOL_H_
 
 #include <string>
 
@@ -19,11 +19,12 @@
   ExampleTool();
   ~ExampleTool();
 
-  std::string GetExample(DBus::Error& error); // NOLINT
+  std::string GetExample(DBus::Error* error);
+
  private:
   DISALLOW_COPY_AND_ASSIGN(ExampleTool);
 };
 
-};  // namespace debugd
+}  // namespace debugd
 
-#endif  // !EXAMPLE_TOOL_H
+#endif  // EXAMPLE_TOOL_H_