Rename interactivity headers in the extensions updater.

The header names have been changed, we need to make a string substitution t
o update them:

X-GoogleUpdate-Interactivity -> X-Goog-Update-Interactivity
X-GoogleUpdate-AppId         -> X-Goog-Update-AppId
X-GoogleUpdate-Updater       -> X-Goog-Update-Updater


Bug: 647516
Change-Id: I147ca276837ece5e9e8c28aa3a871b5ac5cae3b5
Reviewed-on: https://chromium-review.googlesource.com/959555Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Commit-Queue: Sorin Jianu <sorin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542829}

extensions/browser/updater/extension_downloader.cc

@@ -157,10 +157,10 @@ bool IncrementAuthUserIndex(GURL* url) {
 }  // namespace
 
 const char ExtensionDownloader::kUpdateInteractivityHeader[] =
-    "X-GoogleUpdate-Interactivity";
-const char ExtensionDownloader::kUpdateAppIdHeader[] = "X-GoogleUpdate-AppId";
+    "X-Goog-Update-Interactivity";
+const char ExtensionDownloader::kUpdateAppIdHeader[] = "X-Goog-Update-AppId";
 const char ExtensionDownloader::kUpdateUpdaterHeader[] =
-    "X-GoogleUpdate-Updater";
+    "X-Goog-Update-Updater";
 
 const char ExtensionDownloader::kUpdateInteractivityForeground[] = "fg";
 const char ExtensionDownloader::kUpdateInteractivityBackground[] = "bg";