[Chromecast] Copy MainFunctionParams instead of storing reference.

On Android, this was a dangling reference, causing crashes at startup.

Bug: internal b/136249537
Test: CQ
Change-Id: I532e45fc2199ef4e4043931fa10088f4df201216
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1685687
Commit-Queue: Thoren Paulson <thoren@chromium.org>
Reviewed-by: Luke Halliwell <halliwell@chromium.org>
Auto-Submit: Thoren Paulson <thoren@chromium.org>
Cr-Commit-Position: refs/heads/master@{#676213}

chromecast/browser/cast_browser_main_parts.h

@@ -14,6 +14,7 @@
 #include "chromecast/chromecast_buildflags.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_main_parts.h"
+#include "content/public/common/main_function_params.h"
 
 #if defined(OS_ANDROID)
 #include "base/timer/timer.h"
@@ -21,10 +22,6 @@
 
 class PrefService;
 
-namespace content {
-struct MainFunctionParams;
-}
-
 namespace extensions {
 class ExtensionsClient;
 class ExtensionsBrowserClient;
@@ -93,7 +90,7 @@ class CastBrowserMainParts : public content::BrowserMainParts {
 
  private:
   std::unique_ptr<CastBrowserProcess> cast_browser_process_;
-  const content::MainFunctionParams& parameters_;  // For running browser tests.
+  const content::MainFunctionParams parameters_;  // For running browser tests.
   // Caches a pointer of the CastContentBrowserClient.
   CastContentBrowserClient* const cast_content_browser_client_ = nullptr;
   URLRequestContextFactory* const url_request_context_factory_;