Implements migration support for Cast extension users when the Media Router is enabled.

Existing Cast extension users will see the Cast component action in the toolbar.  Media Router users who later install the Cast extension will have the extension auto-unloaded and the component action added to the toolbar.

Adds MIGRATED_TO_COMPONENT extension unload reason, to track when the Cast extension was unloaded because the Media Router was enabled.

Note that there are two public Cast extensions and this design handles both.

BUG=537289
TESTING=Unit tests and manual tests of extension install flows with MR enabled and disabled

Review URL: https://codereview.chromium.org/1368303003

Cr-Commit-Position: refs/heads/master@{#369217}

1 files changed, 2 insertions, 0 deletions

diff --git a/extensions/common/extension.h b/extensions/common/extension.h
index 2363841..ec71517 100644
--- a/extensions/common/extension.h
+++ b/extensions/common/extension.h
@@ -554,6 +554,8 @@ struct UnloadedExtensionInfo {
     REASON_BLACKLIST,         // Extension has been blacklisted.
     REASON_PROFILE_SHUTDOWN,  // Profile is being shut down.
     REASON_LOCK_ALL,          // All extensions for the profile are blocked.
+    REASON_MIGRATED_TO_COMPONENT,  // Extension is being migrated to a component
+                                   // action.
   };
 
   Reason reason;