[PM-11661]Add New Reseed - Fill Buffer Behind Feature Flag (#10905)

* Add New Reseed - Fill Buffer Behind Feature Flag

* Add Tests

* Lint

apps/browser/src/background/main.background.ts

@@ -1463,7 +1463,14 @@ export default class MainBackground {
     });
 
     if (needStorageReseed) {
-      await this.reseedStorage();
+      await this.reseedStorage(
+        await firstValueFrom(
+          this.configService.userCachedFeatureFlag$(
+            FeatureFlag.StorageReseedRefactor,
+            userBeingLoggedOut,
+          ),
+        ),
+      );
     }
 
     if (BrowserApi.isManifestVersion(3)) {
@@ -1518,7 +1525,7 @@ export default class MainBackground {
     await SafariApp.sendMessageToApp("showPopover", null, true);
   }
 
-  async reseedStorage() {
+  async reseedStorage(doFillBuffer: boolean) {
     if (
       !this.platformUtilsService.isChrome() &&
       !this.platformUtilsService.isVivaldi() &&
@@ -1527,7 +1534,11 @@ export default class MainBackground {
       return;
     }
 
-    await this.storageService.reseed();
+    if (doFillBuffer) {
+      await this.storageService.fillBuffer();
+    } else {
+      await this.storageService.reseed();
+    }
   }
 
   async clearClipboard(clipboardValue: string, clearMs: number) {

apps/browser/src/background/runtime.background.ts

@@ -1,4 +1,4 @@
-import { firstValueFrom, map, mergeMap } from "rxjs";
+import { firstValueFrom, map, mergeMap, of, switchMap } from "rxjs";
 
 import { NotificationsService } from "@bitwarden/common/abstractions/notifications.service";
 import { AccountService } from "@bitwarden/common/auth/abstractions/account.service";
@@ -272,9 +272,25 @@ export default class RuntimeBackground {
         await this.main.refreshBadge();
         await this.main.refreshMenu();
         break;
-      case "bgReseedStorage":
-        await this.main.reseedStorage();
+      case "bgReseedStorage": {
+        const doFillBuffer = await firstValueFrom(
+          this.accountService.activeAccount$.pipe(
+            switchMap((account) => {
+              if (account == null) {
+                return of(false);
+              }
+
+              return this.configService.userCachedFeatureFlag$(
+                FeatureFlag.StorageReseedRefactor,
+                account.id,
+              );
+            }),
+          ),
+        );
+
+        await this.main.reseedStorage(doFillBuffer);
         break;
+      }
       case "authResult": {
         const env = await firstValueFrom(this.environmentService.environment$);
         const vaultUrl = env.getWebVaultUrl();

apps/browser/src/platform/services/browser-local-storage.service.ts

@@ -32,6 +32,46 @@ export default class BrowserLocalStorageService extends AbstractChromeStorageSer
     }
   }
 
+  async fillBuffer() {
+    // Write 4MB of data in chrome.storage.local, log files will hold 4MB of data (by default)
+    // before forcing a compaction. To force a compaction and have it remove previously saved data,
+    // we want to fill it's buffer so that anything newly marked for deletion is gone.
+    // https://github.com/google/leveldb/blob/main/doc/impl.md#log-files
+    // It's important that if Google uses a different buffer length that we match that, as far as I can tell
+    // Google uses the default value in Chromium:
+    // https://github.com/chromium/chromium/blob/148774efa6b3a047369af6179a4248566b39d68f/components/value_store/lazy_leveldb.cc#L65-L66
+    const fakeData = "0".repeat(1024 * 1024); // 1MB of data
+    await new Promise<void>((resolve, reject) => {
+      this.chromeStorageApi.set(
+        {
+          fake_data_1: fakeData,
+          fake_data_2: fakeData,
+          fake_data_3: fakeData,
+          fake_data_4: fakeData,
+        },
+        () => {
+          if (chrome.runtime.lastError) {
+            return reject(chrome.runtime.lastError);
+          }
+
+          resolve();
+        },
+      );
+    });
+    await new Promise<void>((resolve, reject) => {
+      this.chromeStorageApi.remove(
+        ["fake_data_1", "fake_data_2", "fake_data_3", "fake_data_4"],
+        () => {
+          if (chrome.runtime.lastError) {
+            return reject(chrome.runtime.lastError);
+          }
+
+          resolve();
+        },
+      );
+    });
+  }
+
   override async get<T>(key: string): Promise<T> {
     await this.awaitReseed();
     return super.get(key);