5 files changed, 45 insertions, 3 deletions

diff --git a/chrome/browser/extensions/extension_service.cc b/chrome/browser/extensions/extension_service.cc
index 834cc4b..7891b83 100644
--- a/chrome/browser/extensions/extension_service.cc
+++ b/chrome/browser/extensions/extension_service.cc
@@ -471,6 +471,14 @@ const ExtensionSet* ExtensionService::terminated_extensions() const {
   return &terminated_extensions_;
 }
 
+const ExtensionSet* ExtensionService::GenerateInstalledExtensionsSet() const {
+  ExtensionSet* installed_extensions = new ExtensionSet();
+  installed_extensions->InsertAll(extensions_);
+  installed_extensions->InsertAll(disabled_extensions_);
+  installed_extensions->InsertAll(terminated_extensions_);
+  return installed_extensions;
+}
+
 PendingExtensionManager* ExtensionService::pending_extension_manager() {
   return &pending_extension_manager_;
 }
diff --git a/chrome/browser/extensions/extension_service.h b/chrome/browser/extensions/extension_service.h
index f5f3fd2..3467812b 100644
--- a/chrome/browser/extensions/extension_service.h
+++ b/chrome/browser/extensions/extension_service.h
@@ -199,6 +199,10 @@ class ExtensionService
   const ExtensionSet* disabled_extensions() const;
   const ExtensionSet* terminated_extensions() const;
 
+  // Retuns a set of all installed, disabled, and terminated extensions and
+  // transfers ownership to caller.
+  const ExtensionSet* GenerateInstalledExtensionsSet() const;
+
   // Gets the object managing the set of pending extensions.
   virtual PendingExtensionManager* pending_extension_manager() OVERRIDE;
 
diff --git a/chrome/common/extensions/extension_set.cc b/chrome/common/extensions/extension_set.cc
index d6d18f7..f5aee9f 100644
--- a/chrome/common/extensions/extension_set.cc
+++ b/chrome/common/extensions/extension_set.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -41,6 +41,15 @@ void ExtensionSet::Insert(const scoped_refptr<const Extension>& extension) {
   extensions_[extension->id()] = extension;
 }
 
+bool ExtensionSet::InsertAll(const ExtensionSet& extensions) {
+  size_t before = size();
+  for (ExtensionSet::const_iterator iter = extensions.begin();
+       iter != extensions.end(); ++iter) {
+    Insert(*iter);
+  }
+  return size() != before;
+}
+
 void ExtensionSet::Remove(const std::string& id) {
   extensions_.erase(id);
 }
diff --git a/chrome/common/extensions/extension_set.h b/chrome/common/extensions/extension_set.h
index 87edae1..9d46373 100644
--- a/chrome/common/extensions/extension_set.h
+++ b/chrome/common/extensions/extension_set.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -85,6 +85,10 @@ class ExtensionSet {
   // previous extension with the same ID is removed.
   void Insert(const scoped_refptr<const Extension>& extension);
 
+  // Copies different items from |extensions| to the current set and returns
+  // whether anything changed.
+  bool InsertAll(const ExtensionSet& extensions);
+
   // Removes the specified extension.
   void Remove(const std::string& id);
 
diff --git a/chrome/common/extensions/extension_set_unittest.cc b/chrome/common/extensions/extension_set_unittest.cc
index 56f2b5f..37e5559 100644
--- a/chrome/common/extensions/extension_set_unittest.cc
+++ b/chrome/common/extensions/extension_set_unittest.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -114,4 +114,21 @@ TEST(ExtensionSetTest, ExtensionSet) {
   extensions.Remove(ext2->id());
   EXPECT_EQ(2u, extensions.size());
   EXPECT_FALSE(extensions.GetByID(ext2->id()));
+
+  // Make a union of a set with 3 more extensions (only 2 are new).
+  scoped_refptr<Extension> ext5(CreateTestExtension("d", "", ""));
+  scoped_refptr<Extension> ext6(CreateTestExtension("e", "", ""));
+  ASSERT_TRUE(ext5 && ext6);
+
+  scoped_ptr<ExtensionSet> to_add(new ExtensionSet());
+  to_add->Insert(ext3);  // Already in |extensions|, should not affect size.
+  to_add->Insert(ext5);
+  to_add->Insert(ext6);
+
+  ASSERT_TRUE(extensions.Contains(ext3->id()));
+  ASSERT_TRUE(extensions.InsertAll(*to_add));
+  EXPECT_EQ(4u, extensions.size());
+
+  ASSERT_FALSE(extensions.InsertAll(*to_add));  // Re-adding same set no-ops.
+  EXPECT_EQ(4u, extensions.size());
 }