Made it possible to tell whether an extension is being installed or updated.

chrome/common/extensions/extension.h

Index: chrome/common/extensions/extension.h
diff --git a/chrome/common/extensions/extension.h b/chrome/common/extensions/extension.h
index 10b143023e91713896440f3ee62abf76bd1a9949..f67904ddd85d922f103de82700c46294a41f8664 100644
--- a/chrome/common/extensions/extension.h
+++ b/chrome/common/extensions/extension.h
@@ -697,6 +697,17 @@ struct ExtensionInfo {
   DISALLOW_COPY_AND_ASSIGN(ExtensionInfo);
 };
 
+struct InstalledExtensionInfo {
+  // The extension being installed - this should always be non-NULL.
+  const Extension* extension;
+
+  // Was the extension already installed? (If true, this means the extension is
+  // being updated.)
+  bool already_installed;

[benwells, 2013/05/02 01:40:08]

I think this is more clear if it is just called is_update.

[Matt Giuca, 2013/05/02 05:40:33]

Done.

+
+  InstalledExtensionInfo(const Extension* extension, bool already_installed);
+};
+
 struct UnloadedExtensionInfo {
   extension_misc::UnloadedExtensionReason reason;