Fix WebApkInstallService::IsInstallInProgress() crash.

chrome/browser/android/webapk/webapk_install_service_factory.h

Index: chrome/browser/android/webapk/webapk_install_service_factory.h
diff --git a/chrome/browser/android/webapk/webapk_install_service_factory.h b/chrome/browser/android/webapk/webapk_install_service_factory.h
index 599a081179e02cf73a0654e597e65daab185364a..35b5771c1d2f5efa171281e2d360d7b6f8b9f6c4 100644
--- a/chrome/browser/android/webapk/webapk_install_service_factory.h
+++ b/chrome/browser/android/webapk/webapk_install_service_factory.h
@@ -28,6 +28,9 @@ class WebApkInstallServiceFactory : public BrowserContextKeyedServiceFactory {
   KeyedService* BuildServiceInstanceFor(
       content::BrowserContext* context) const override;
 
+  content::BrowserContext* GetBrowserContextToUse(
+      content::BrowserContext* context) const override;
+
   DISALLOW_COPY_AND_ASSIGN(WebApkInstallServiceFactory);
 };