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..fca1e758996a7c3cf927f26ba877838af11a2e3a 100644
--- a/chrome/browser/component_updater/component_patcher.h
+++ b/chrome/browser/component_updater/component_patcher.h
@@ -38,6 +38,8 @@ class FilePath;
 
 class ComponentInstaller;
 
+namespace component_updater {
+
 // Applies a delta patch to a single file. Specifically, creates a file at
 // |output_file| using |input_file| patched according to the algorithm
 // specified by |patch_type| using |patch_file|. Sets the value of error to
@@ -51,22 +53,24 @@ class ComponentPatcher {
     kPatchTypeBsdiff,
   };
 
-  virtual ComponentUnpacker::Error Patch(PatchType patch_type,
-                                         const base::FilePath& input_file,
-                                         const base::FilePath& patch_file,
-                                         const base::FilePath& output_file,
-                                         int* error) = 0;
+  virtual ComponentUnpacker::Error Patch(
+      PatchType patch_type,
+      const base::FilePath& input_file,
+      const base::FilePath& patch_file,
+      const base::FilePath& output_file,
+      int* error) = 0;
   virtual ~ComponentPatcher() {}
 };
 
 class ComponentPatcherCrossPlatform : public ComponentPatcher {
  public:
   ComponentPatcherCrossPlatform();
-  virtual ComponentUnpacker::Error Patch(PatchType patch_type,
-                                         const base::FilePath& input_file,
-                                         const base::FilePath& patch_file,
-                                         const base::FilePath& output_file,
-                                         int* error) OVERRIDE;
+  virtual ComponentUnpacker::Error Patch(
+      PatchType patch_type,
+      const base::FilePath& input_file,
+      const base::FilePath& patch_file,
+      const base::FilePath& output_file,
+      int* error) OVERRIDE;
  private:
   DISALLOW_COPY_AND_ASSIGN(ComponentPatcherCrossPlatform);
 };
@@ -75,12 +79,16 @@ 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(ComponentUnpacker::Error, int)>
+    callback);
+
+}  // namespace component_updater
 
 #endif  // CHROME_BROWSER_COMPONENT_UPDATER_COMPONENT_PATCHER_H_