Change userid from a uint32_t to a string guid

content/public/browser/browser_context.h

Index: content/public/browser/browser_context.h
diff --git a/content/public/browser/browser_context.h b/content/public/browser/browser_context.h
index 26a208ca8d8e85937aba356a0440ee3797e048dd..6f199bbe3fb3cc96da2914d03b09785527fa3d1c 100644
--- a/content/public/browser/browser_context.h
+++ b/content/public/browser/browser_context.h
@@ -133,9 +133,9 @@ class CONTENT_EXPORT BrowserContext : public base::SupportsUserData {
   static void Initialize(BrowserContext* browser_context,
                          const base::FilePath& path);
 
-  // Returns a randomized user ID number associated with this
-  // BrowserContext. This ID is not persistent across runs.
-  static uint32_t GetMojoUserIdFor(BrowserContext* browser_context);
+  // Returns a Mojo User ID associated with this BrowserContext. This ID is not
+  // persistent across runs. See mojo/shell/public/interfaces/connector.mojom.
+  static const std::string& GetMojoUserIdFor(BrowserContext* browser_context);
 
   ~BrowserContext() override;