From 5ebb7a4795ee59b70266ec9a1373ef144be49e76 Mon Sep 17 00:00:00 2001
From: Boris Zbarsky <bzbarsky@mit.edu>
Date: Wed, 23 Mar 2016 11:02:57 -0400
Subject: [PATCH] Bug 1257725 part 4.  Get rid of ThreadsafeAutoJSContext usage
 in IndexedDB code, except for IDBRequest::CaptureCaller.  r=khuey

---
 dom/indexedDB/IDBDatabase.cpp            | 24 ++++--------------------
 dom/indexedDB/IndexedDatabaseManager.cpp |  3 +--
 2 files changed, 5 insertions(+), 22 deletions(-)

diff --git a/dom/indexedDB/IDBDatabase.cpp b/dom/indexedDB/IDBDatabase.cpp
index c72a4921517b..08351d77ad0f 100644
--- a/dom/indexedDB/IDBDatabase.cpp
+++ b/dom/indexedDB/IDBDatabase.cpp
@@ -607,32 +607,16 @@ IDBDatabase::Transaction(const StringOrStringSequence& aStoreNames,
 {
   AssertIsOnOwningThread();
 
-  aRv.MightThrowJSException();
-
   if ((aMode == IDBTransactionMode::Readwriteflush ||
        aMode == IDBTransactionMode::Cleanup) &&
       !IndexedDatabaseManager::ExperimentalFeaturesEnabled()) {
     // Pretend that this mode doesn't exist. We don't have a way to annotate
     // certain enum values as depending on preferences so we just duplicate the
     // normal exception generation here.
-    ThreadsafeAutoJSContext cx;
-
-    // Disable any automatic error reporting that might be set up so that we
-    // can grab the exception object.
-    AutoForceSetExceptionOnContext forceExn(cx);
-
-    MOZ_ALWAYS_FALSE(
-      ThrowErrorMessage(cx,
-                        MSG_INVALID_ENUM_VALUE,
-                        "Argument 2 of IDBDatabase.transaction",
-                        "readwriteflush",
-                        "IDBTransactionMode"));
-    MOZ_ASSERT(JS_IsExceptionPending(cx));
-
-    JS::Rooted<JS::Value> exception(cx);
-    MOZ_ALWAYS_TRUE(JS_GetPendingException(cx, &exception));
-
-    aRv.ThrowJSException(cx, exception);
+    aRv.ThrowTypeError<MSG_INVALID_ENUM_VALUE>(
+      NS_LITERAL_STRING("Argument 2 of IDBDatabase.transaction"),
+      NS_LITERAL_STRING("readwriteflush"),
+      NS_LITERAL_STRING("IDBTransactionMode"));
     return nullptr;
   }
 
diff --git a/dom/indexedDB/IndexedDatabaseManager.cpp b/dom/indexedDB/IndexedDatabaseManager.cpp
index eaa38e16ec80..b6061bc549e0 100644
--- a/dom/indexedDB/IndexedDatabaseManager.cpp
+++ b/dom/indexedDB/IndexedDatabaseManager.cpp
@@ -484,8 +484,7 @@ IndexedDatabaseManager::CommonPostHandleEvent(EventChainPostVisitor& aVisitor,
     error->GetName(errorName);
   }
 
-  ThreadsafeAutoJSContext cx;
-  RootedDictionary<ErrorEventInit> init(cx);
+  RootedDictionary<ErrorEventInit> init(nsContentUtils::RootingCxForThread());
   request->GetCallerLocation(init.mFilename, &init.mLineno, &init.mColno);
 
   init.mMessage = errorName;