[CSC] Crash fix for browser

(cherry picked from commit 758edd6)

Bug: 1453864
Change-Id: I89f057e49f1a8837c9f61f03862fa089e0f74874
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4609387
Reviewed-by: Michael Crouse <mcrouse@chromium.org>
Commit-Queue: Shakti Sahu <shaktisahu@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1157666}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4618413
Cr-Commit-Position: refs/branch-heads/5790@{#799}
Cr-Branched-From: 1d71a33-refs/heads/main@{#1148114}

chrome/browser/ui/views/side_panel/search_companion/companion_side_panel_controller_utils.cc

@@ -20,8 +20,7 @@ Browser* GetBrowserForWebContents(content::WebContents* web_contents) {
   auto* browser_window =
       BrowserWindow::FindBrowserWindowWithWebContents(web_contents);
   auto* browser_view = static_cast<BrowserView*>(browser_window);
-  CHECK(browser_view);
-  return browser_view->browser();
+  return browser_view ? browser_view->browser() : nullptr;
 }
 
 }  // namespace companion

chrome/browser/ui/webui/side_panel/companion/companion_page_handler.cc

@@ -135,6 +135,11 @@ void CompanionPageHandler::ShowUI() {
     // Calls to the browser need to happen after the ShowUI() call above since
     // it is only added to browser hierarchy after the side panel has loaded the
     // page.
+    auto* browser = GetBrowser();
+    if (!browser) {
+      return;
+    }
+
     auto* active_web_contents =
         GetBrowser()->tab_strip_model()->GetActiveWebContents();
     Observe(active_web_contents);

chrome/browser/ui/webui/side_panel/companion/signin_delegate_impl.cc

@@ -77,13 +77,17 @@ void SigninDelegateImpl::EnableMsbb(bool enable_msbb) {
 }
 
 void SigninDelegateImpl::OpenUrlInBrowser(const GURL& url, bool use_new_tab) {
+  auto* browser = companion::GetBrowserForWebContents(webui_contents_);
+  if (!browser) {
+    return;
+  }
+
   content::OpenURLParams params(url, content::Referrer(),
                                 use_new_tab
                                     ? WindowOpenDisposition::NEW_FOREGROUND_TAB
                                     : WindowOpenDisposition::CURRENT_TAB,
                                 ui::PAGE_TRANSITION_AUTO_TOPLEVEL,
                                 /*is_renderer_initiated*/ false);
-  auto* browser = companion::GetBrowserForWebContents(webui_contents_);
   browser->OpenURL(params);
 }