SandboxedUnpacker: Prevent unnecessary PostTask while reporting failure.

SandboxedUnpacker::ReportUnpackingError posts a task on the
|unpacker_io_task_runner_| to report unpacking failures. However, all its
callers are on |unpacker_io_task_runner_| itself. Prevent unnecessarily posting
a task by merging ReportUnpackingError and UnpackExtensionFailed methods.

BUG=None

Change-Id: Id229392333d0236fd60a5cce0cf642f3aa436ab8
Reviewed-on: https://chromium-review.googlesource.com/1108574
Commit-Queue: Karan Bhatia <karandeepb@chromium.org>
Reviewed-by: Jay Civelli <jcivelli@chromium.org>
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569167}

extensions/browser/sandboxed_unpacker.cc

@@ -437,11 +437,11 @@ void SandboxedUnpacker::ReadManifestDone(
     const base::Optional<std::string>& error) {
   DCHECK(unpacker_io_task_runner_->RunsTasksInCurrentSequence());
   if (error) {
-    ReportUnpackingError(*error);
+    ReportUnpackExtensionFailed(*error);
     return;
   }
   if (!manifest || !manifest->is_dict()) {
-    ReportUnpackingError(manifest_errors::kInvalidManifest);
+    ReportUnpackExtensionFailed(manifest_errors::kInvalidManifest);
     return;
   }
 
@@ -454,13 +454,13 @@ void SandboxedUnpacker::ReadManifestDone(
       Extension::Create(extension_root_, location_, *manifest_dict,
                         creation_flags_, extension_id_, &error_msg));
   if (!extension) {
-    ReportUnpackingError(error_msg);
+    ReportUnpackExtensionFailed(error_msg);
     return;
   }
 
   std::vector<InstallWarning> warnings;
   if (!file_util::ValidateExtension(extension.get(), &error_msg, &warnings)) {
-    ReportUnpackingError(error_msg);
+    ReportUnpackExtensionFailed(error_msg);
     return;
   }
   extension->AddInstallWarnings(warnings);
@@ -702,12 +702,13 @@ void SandboxedUnpacker::ReadJSONRulesetDone(
   DCHECK(unpacker_io_task_runner_->RunsTasksInCurrentSequence());
 
   if (error) {
-    ReportUnpackingError(*error);
+    ReportUnpackExtensionFailed(*error);
     return;
   }
 
   if (json_ruleset && !json_ruleset->is_list()) {
-    ReportUnpackingError(manifest_errors::kDeclarativeNetRequestListNotPassed);
+    ReportUnpackExtensionFailed(
+        manifest_errors::kDeclarativeNetRequestListNotPassed);
     return;
   }
 
@@ -776,17 +777,11 @@ data_decoder::mojom::JsonParser* SandboxedUnpacker::GetJsonParserPtr() {
   return json_parser_ptr_.get();
 }
 
-void SandboxedUnpacker::ReportUnpackingError(base::StringPiece error) {
-  unpacker_io_task_runner_->PostTask(
-      FROM_HERE, base::BindOnce(&SandboxedUnpacker::UnpackExtensionFailed, this,
-                                base::UTF8ToUTF16(error)));
-}
-
-void SandboxedUnpacker::UnpackExtensionFailed(const base::string16& error) {
+void SandboxedUnpacker::ReportUnpackExtensionFailed(base::StringPiece error) {
   DCHECK(unpacker_io_task_runner_->RunsTasksInCurrentSequence());
-  ReportFailure(
-      SandboxedUnpackerFailureReason::UNPACKER_CLIENT_FAILED,
-      l10n_util::GetStringFUTF16(IDS_EXTENSION_PACKAGE_ERROR_MESSAGE, error));
+  ReportFailure(SandboxedUnpackerFailureReason::UNPACKER_CLIENT_FAILED,
+                l10n_util::GetStringFUTF16(IDS_EXTENSION_PACKAGE_ERROR_MESSAGE,
+                                           base::UTF8ToUTF16(error)));
 }
 
 base::string16 SandboxedUnpacker::FailureReasonToString16(

extensions/browser/sandboxed_unpacker.h

@@ -62,6 +62,9 @@ class SandboxedUnpackerClient
   // dnr_ruleset_checksum - Checksum for the indexed ruleset corresponding to
   // the Declarative Net Request API. Optional since it's only valid for
   // extensions which provide a declarative ruleset.
+  //
+  // Note: OnUnpackSuccess/Failure may be called either synchronously or
+  // asynchronously from SandboxedUnpacker::StartWithCrx/Directory.
   virtual void OnUnpackSuccess(
       const base::FilePath& temp_dir,
       const base::FilePath& extension_root,
@@ -163,9 +166,9 @@ class SandboxedUnpacker : public base::RefCountedThreadSafe<SandboxedUnpacker> {
                         const base::Optional<std::string>& error);
   void UnpackExtensionSucceeded(
       std::unique_ptr<base::DictionaryValue> manifest);
-  void UnpackExtensionFailed(const base::string16& error);
 
-  void ReportUnpackingError(base::StringPiece error);
+  // Helper which calls ReportFailure.
+  void ReportUnpackExtensionFailed(base::StringPiece error);
 
   void ImageSanitizationDone(std::unique_ptr<base::DictionaryValue> manifest,
                              ImageSanitizer::Status status,