Create thread-safe RendererExtensionRegistry from ExtensionSet

extensions/renderer/renderer_extension_registry.h

Index: extensions/renderer/renderer_extension_registry.h
diff --git a/extensions/renderer/renderer_extension_registry.h b/extensions/renderer/renderer_extension_registry.h
new file mode 100644
index 0000000000000000000000000000000000000000..4802875fd5ffcc82760cb79968116752b1a4318a
--- /dev/null
+++ b/extensions/renderer/renderer_extension_registry.h
@@ -0,0 +1,82 @@
+// Copyright 2015 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_RENDERER_RENDERER_EXTENSION_REGISTRY_H_
+#define EXTENSIONS_RENDERER_RENDERER_EXTENSION_REGISTRY_H_
+
+#include <iterator>
+#include <string>
+
+#include "base/synchronization/lock.h"
+#include "extensions/common/extension.h"
+#include "extensions/common/extension_set.h"
+#include "url/gurl.h"
+
+namespace extensions {
+
+// Thread safe container for all loaded extensions in this process,
+// essentially the renderer counterpart to ExtensionRegistry.
+class RendererExtensionRegistry {
+ public:
+  RendererExtensionRegistry();
+  ~RendererExtensionRegistry();
+
+  static RendererExtensionRegistry* Get();
+
+  const ExtensionSet* GetMainThreadExtensionSet() const;

[Devlin, 2015/08/18 15:40:55]

This should definitely have a comment, and probably a TODO to remove it (I think
it's mostly just a hack that we need it).

[annekao, 2015/08/18 17:43:31]

Done.

+
+  size_t size() const;
+  bool is_empty() const;
+
+  // Iteration support.
+  ExtensionSet::const_iterator begin() const { return extensions_.begin(); }

[Devlin, 2015/08/18 15:40:55]

This is thread-unsafe.  If the main thread acquires an iterator, and another
thread inserts an extension, and then the main thread uses the iterator, bad
stuff happens.  I think if something *really* needs an iterator (it should be
rare, I think), it should just grab the full ExtensionSet.

[annekao, 2015/08/18 17:43:31]

Done.  Used in IsRuntimeAvailableToConnect() and UpdateContentCapabilities() in
Dispatcher.

+  ExtensionSet::const_iterator end() const { return extensions_.end(); }
+
+  // Returns true if the set contains the specified extension.
+  bool Contains(const std::string& id) const;

[Devlin, 2015/08/18 15:40:55]

I think for these you can (and probably should) just say "Forwards to the
ExtensionSet methods by the same name."  That way, we don't have to update the
comments if/when those change.

[annekao, 2015/08/18 17:43:31]

Done.

+
+  // Adds the specified extension to the set. The set becomes an owner. Any
+  // previous extension with the same ID is removed.
+  // Returns true if there is no previous extension.
+  bool Insert(const scoped_refptr<const Extension>& extension);
+
+  // Removes the specified extension.
+  // Returns true if the set contained the specified extnesion.
+  bool Remove(const std::string& id);
+
+  // Returns the extension ID, or empty if none. This includes web URLs that
+  // are part of an extension's web extent.
+  std::string GetExtensionOrAppIDByURL(const GURL& url) const;
+
+  // Returns the Extension, or NULL if none.  This includes web URLs that are
+  // part of an extension's web extent.
+  // NOTE: This can return NULL if called before UpdateExtensions receives
+  // bulk extension data (e.g. if called from
+  // EventBindings::HandleContextCreated)
+  const Extension* GetExtensionOrAppByURL(const GURL& url) const;
+
+  const Extension* GetHostedAppByURL(const GURL& url) const;
+
+  // Look up an Extension object by id.
+  const Extension* GetByID(const std::string& id) const;
+
+  // Gets the IDs of all extensions in the set.
+  ExtensionIdSet GetIDs() const;
+
+  // Returns true if |info| should get extension api bindings and be permitted
+  // to make api calls. Note that this is independent of what extension
+  // permissions the given extension has been granted.
+  bool ExtensionBindingsAllowed(const GURL& url) const;
+
+ private:
+  ExtensionSet extensions_;
+
+  mutable base::Lock lock_;
+
+  DISALLOW_COPY_AND_ASSIGN(RendererExtensionRegistry);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_RENDERER_RENDERER_EXTENSION_REGISTRY_H_