Remove LifetimeObserver which was a proxy for a WeakPtr<WebContents>

Use GetWeakPtr directly for having a reference to a WebContents. The
proxy was unnecessary with the newly added method on WebContents.

BUG=952390

Change-Id: Ib603d74919cb295e73b0255118d18a804c04a80b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3145471
Reviewed-by: Glenn Hartmann <[email protected]>
Commit-Queue: Dave Tapuska <[email protected]>
Cr-Commit-Position: refs/heads/main@{#918849}

Author: dtapuska

chrome/browser/android/webapk/webapk_install_service.cc

@@ -15,6 +15,7 @@
 #include "chrome/browser/android/webapk/webapk_install_service_factory.h"
 #include "chrome/browser/android/webapk/webapk_installer.h"
 #include "components/webapps/browser/android/shortcut_info.h"
+#include "content/public/browser/web_contents.h"
 #include "ui/gfx/android/java_bitmap.h"
 
 // static
@@ -50,14 +51,13 @@ void WebApkInstallService::InstallAsync(
   ShowInstallInProgressNotification(shortcut_info, primary_icon,
                                     is_primary_icon_maskable);
 
-  // We pass an observer which wraps the WebContents to the callback, since the
+  // We pass an weak ptr to a WebContents to the callback, since the
   // installation may take more than 10 seconds so there is a chance that the
   // WebContents has been destroyed before the install is finished.
-  auto observer = std::make_unique<LifetimeObserver>(web_contents);
   WebApkInstaller::InstallAsync(
       browser_context_, shortcut_info, primary_icon, is_primary_icon_maskable,
       base::BindOnce(&WebApkInstallService::OnFinishedInstall,
-                     weak_ptr_factory_.GetWeakPtr(), std::move(observer),
+                     weak_ptr_factory_.GetWeakPtr(), web_contents->GetWeakPtr(),
                      shortcut_info, primary_icon, is_primary_icon_maskable));
 }
 
@@ -69,7 +69,7 @@ void WebApkInstallService::UpdateAsync(
 }
 
 void WebApkInstallService::OnFinishedInstall(
-    std::unique_ptr<LifetimeObserver> observer,
+    base::WeakPtr<content::WebContents> web_contents,
     const webapps::ShortcutInfo& shortcut_info,
     const SkBitmap& primary_icon,
     bool is_primary_icon_maskable,
@@ -94,12 +94,11 @@ void WebApkInstallService::OnFinishedInstall(
   // happen if Play was busy with another install and this one is still queued
   // (and hence might succeed in the future).
   if (result == WebApkInstallResult::FAILURE) {
-    content::WebContents* web_contents = observer->web_contents();
     if (!web_contents)
       return;
 
     // TODO(https://crbug.com/861643): Support maskable icons here.
-    ShortcutHelper::AddToLauncherWithSkBitmap(web_contents, shortcut_info,
+    ShortcutHelper::AddToLauncherWithSkBitmap(web_contents.get(), shortcut_info,
                                               primary_icon,
                                               /*is_icon_maskable=*/false);
   }

chrome/browser/android/webapk/webapk_install_service.h

@@ -16,7 +16,6 @@
 #include "base/memory/weak_ptr.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "components/webapps/browser/installable/installable_metrics.h"
-#include "content/public/browser/web_contents_observer.h"
 #include "url/gurl.h"
 
 namespace base {
@@ -83,18 +82,8 @@ class WebApkInstallService : public KeyedService {
                    FinishCallback finish_callback);
 
  private:
-  // Observes the lifetime of a WebContents.
-  class LifetimeObserver : public content::WebContentsObserver {
-   public:
-    explicit LifetimeObserver(content::WebContents* web_contents)
-        : WebContentsObserver(web_contents) {}
-
-   private:
-    DISALLOW_COPY_AND_ASSIGN(LifetimeObserver);
-  };
-
   // Called once the install/update completed or failed.
-  void OnFinishedInstall(std::unique_ptr<LifetimeObserver> observer,
+  void OnFinishedInstall(base::WeakPtr<content::WebContents> web_contents,
                          const webapps::ShortcutInfo& shortcut_info,
                          const SkBitmap& primary_icon,
                          bool is_priamry_icon_maskable,