Move ExtensionCache to //extensions

This moves the ExtensionCache interface out to extensions and
delegates instance provisioning out to ExtensionsBrowserClient
implementations.

BUG=398671

Review URL: https://codereview.chromium.org/612423003

Cr-Commit-Position: refs/heads/master@{#299192}

3 files changed, 140 insertions, 0 deletions

diff --git a/extensions/browser/updater/extension_cache.h b/extensions/browser/updater/extension_cache.h
new file mode 100644
index 0000000..f6bdb02
--- /dev/null
+++ b/extensions/browser/updater/extension_cache.h
@@ -0,0 +1,63 @@
+// Copyright 2014 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 EXTENSIONS_BROWSER_UPDATER_EXTENSION_CACHE_H_
+#define EXTENSIONS_BROWSER_UPDATER_EXTENSION_CACHE_H_
+
+#include <string>
+
+#include "base/callback_forward.h"
+#include "base/files/file_path.h"
+
+namespace extensions {
+
+// ExtensionCache interface that caches extensions .crx files to share them
+// between multiple users and profiles on the machine.
+class ExtensionCache {
+ public:
+  // Callback that is invoked when the file placed when PutExtension done.
+  typedef base::Callback<void(const base::FilePath& file_path,
+                              bool file_ownership_passed)> PutExtensionCallback;
+
+  ExtensionCache() {}
+  virtual ~ExtensionCache() {}
+
+  // Initialize cache in background. The |callback| is called when cache ready.
+  // Can be called multiple times. The |callback| can be called immediately if
+  // cache is ready.
+  virtual void Start(const base::Closure& callback) = 0;
+
+  // Shut down the cache. Must be called at most once on browser shutdown.
+  virtual void Shutdown(const base::Closure& callback) = 0;
+
+  // Allow caching for the extension with given |id|. User specific extensions
+  // should not be cached for privacy reasons. But default apps including policy
+  // configured can be cached. Can be called before Init.
+  virtual void AllowCaching(const std::string& id) = 0;
+
+  // If extension with |id| exists in the cache, returns |true|, |file_path| and
+  // |version| for the extension. Extension will be marked as used with current
+  // timestamp.
+  virtual bool GetExtension(const std::string& id,
+                            base::FilePath* file_path,
+                            std::string* version) = 0;
+
+  // Put extension with |id| and |version| into local cache. Older version in
+  // the cache will removed be on next run so it can be safely used. Extension
+  // will be marked as used with current timestamp. The file will be available
+  // via GetExtension when |callback| is called. Original |file_path| won't be
+  // deleted from the disk. There is no guarantee that |callback| will be
+  // called.
+  virtual void PutExtension(const std::string& id,
+                            const base::FilePath& file_path,
+                            const std::string& version,
+                            const PutExtensionCallback& callback) = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ExtensionCache);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_UPDATER_EXTENSION_CACHE_H_
diff --git a/extensions/browser/updater/null_extension_cache.cc b/extensions/browser/updater/null_extension_cache.cc
new file mode 100644
index 0000000..3241d20
--- /dev/null
+++ b/extensions/browser/updater/null_extension_cache.cc
@@ -0,0 +1,41 @@
+// Copyright 2014 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.
+
+#include "extensions/browser/updater/null_extension_cache.h"
+
+#include "base/callback.h"
+
+namespace extensions {
+
+NullExtensionCache::NullExtensionCache() {
+}
+
+NullExtensionCache::~NullExtensionCache() {
+}
+
+void NullExtensionCache::Start(const base::Closure& callback) {
+  callback.Run();
+}
+
+void NullExtensionCache::Shutdown(const base::Closure& callback) {
+  callback.Run();
+}
+
+void NullExtensionCache::AllowCaching(const std::string& id) {
+}
+
+bool NullExtensionCache::GetExtension(const std::string& id,
+                                      base::FilePath* file_path,
+                                      std::string* version) {
+  return false;
+}
+
+void NullExtensionCache::PutExtension(const std::string& id,
+                                      const base::FilePath& file_path,
+                                      const std::string& version,
+                                      const PutExtensionCallback& callback) {
+  callback.Run(file_path, true);
+}
+
+}  // namespace extensions
diff --git a/extensions/browser/updater/null_extension_cache.h b/extensions/browser/updater/null_extension_cache.h
new file mode 100644
index 0000000..c4c9a1b
--- /dev/null
+++ b/extensions/browser/updater/null_extension_cache.h
@@ -0,0 +1,36 @@
+// Copyright 2014 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 EXTENSIONS_BROWSER_UPDATER_NULL_EXTENSION_CACHE_H_
+#define EXTENSIONS_BROWSER_UPDATER_NULL_EXTENSION_CACHE_H_
+
+#include "extensions/browser/updater/extension_cache.h"
+
+namespace extensions {
+
+// Implements a pass-thru (i.e. do-nothing) ExtensionCache.
+class NullExtensionCache : public ExtensionCache {
+ public:
+  NullExtensionCache();
+  virtual ~NullExtensionCache();
+
+  // ExtensionCache implementation.
+  virtual void Start(const base::Closure& callback) override;
+  virtual void Shutdown(const base::Closure& callback) override;
+  virtual void AllowCaching(const std::string& id) override;
+  virtual bool GetExtension(const std::string& id,
+                            base::FilePath* file_path,
+                            std::string* version) override;
+  virtual void PutExtension(const std::string& id,
+                            const base::FilePath& file_path,
+                            const std::string& version,
+                            const PutExtensionCallback& callback) override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(NullExtensionCache);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_UPDATER_NULL_EXTENSION_CACHE_H_