Support asynchronous patching operations in the component updater.

chrome/browser/component_updater/component_patcher.h

Index: chrome/browser/component_updater/component_patcher.h
diff --git a/chrome/browser/component_updater/component_patcher.h b/chrome/browser/component_updater/component_patcher.h
index 1990922dac9c3d024d6eb65c14f83609b503355b..215ea717ed9c2ef4a475d1ac72a3dee3389b594c 100644
--- a/chrome/browser/component_updater/component_patcher.h
+++ b/chrome/browser/component_updater/component_patcher.h
@@ -51,7 +51,7 @@ class ComponentPatcher {
     kPatchTypeBsdiff,
   };
 
-  virtual ComponentUnpacker::Error Patch(PatchType patch_type,
+  virtual component_updater::Error Patch(PatchType patch_type,
                                          const base::FilePath& input_file,
                                          const base::FilePath& patch_file,
                                          const base::FilePath& output_file,
@@ -62,7 +62,7 @@ class ComponentPatcher {
 class ComponentPatcherCrossPlatform : public ComponentPatcher {
  public:
   ComponentPatcherCrossPlatform();
-  virtual ComponentUnpacker::Error Patch(PatchType patch_type,
+  virtual component_updater::Error Patch(PatchType patch_type,
                                          const base::FilePath& input_file,
                                          const base::FilePath& patch_file,
                                          const base::FilePath& output_file,
@@ -75,12 +75,13 @@ class ComponentPatcherCrossPlatform : public ComponentPatcher {
 // component installer, and creates a new (non-differential) unpacked CRX, which
 // is then installed normally.
 // The non-differential files are written into the |unpack_dir| directory.
-// Sets |error| to the error code of the first failing patch operation.
-ComponentUnpacker::Error DifferentialUpdatePatch(
+// When finished, calls the callback, passing error codes if any errors were
+// encountered.
+void DifferentialUpdatePatch(
     const base::FilePath& input_dir,
     const base::FilePath& unpack_dir,
     ComponentPatcher* component_patcher,
     ComponentInstaller* installer,
-    int* error);
+    base::Callback<void(component_updater::Error, int)> callback);
 
 #endif  // CHROME_BROWSER_COMPONENT_UPDATER_COMPONENT_PATCHER_H_