Move most of the component updater artifacts to update_client.

components/component_updater/default_component_installer.h

Index: components/component_updater/default_component_installer.h
diff --git a/components/component_updater/default_component_installer.h b/components/component_updater/default_component_installer.h
index 3946ab390ffcbebd6e0a1faa99a7a8f4501c1d83..120d3a5de8cd44ae484120ee7633aa326e7661cd 100644
--- a/components/component_updater/default_component_installer.h
+++ b/components/component_updater/default_component_installer.h
@@ -16,7 +16,7 @@
 #include "base/threading/thread_checker.h"
 #include "base/values.h"
 #include "base/version.h"
-#include "components/component_updater/component_updater_service.h"
+#include "components/update_client/update_client.h"
 
 namespace base {
 class FilePath;
@@ -26,6 +26,8 @@ class SingleThreadTaskRunner;
 
 namespace component_updater {
 
+class ComponentUpdateService;
+
 // Components should use a DefaultComponentInstaller by defining a class that
 // implements the members of ComponentInstallerTraits, and then registering a
 // DefaultComponentInstaller that has been constructed with an instance of that
@@ -82,7 +84,7 @@ class ComponentInstallerTraits {
 // A DefaultComponentInstaller is intended to be final, and not derived from.
 // Customization must be provided by passing a ComponentInstallerTraits object
 // to the constructor.
-class DefaultComponentInstaller : public ComponentInstaller {
+class DefaultComponentInstaller : public update_client::ComponentInstaller {
  public:
   DefaultComponentInstaller(
       scoped_ptr<ComponentInstallerTraits> installer_traits);