From a1ff54a54f03fc51819796082430c278db458814 Mon Sep 17 00:00:00 2001
From: Cameron McCormack <cam@mcc.id.au>
Date: Wed, 4 Mar 2020 18:25:08 +0000
Subject: [PATCH] Bug 1607356 - Move OTS sanitization to background thread.
 r=KrisWright

Differential Revision: https://phabricator.services.mozilla.com/D65267

--HG--
extra : moz-landing-system : lando
---
 gfx/thebes/gfxUserFontSet.cpp    | 20 +++++---------------
 gfx/thebes/gfxUserFontSet.h      |  8 ++------
 layout/build/nsLayoutStatics.cpp |  2 --
 3 files changed, 7 insertions(+), 23 deletions(-)

diff --git a/gfx/thebes/gfxUserFontSet.cpp b/gfx/thebes/gfxUserFontSet.cpp
index 0e8945ab1ec1..b752ac6b2054 100644
--- a/gfx/thebes/gfxUserFontSet.cpp
+++ b/gfx/thebes/gfxUserFontSet.cpp
@@ -705,11 +705,10 @@ bool gfxUserFontEntry::LoadPlatformFontSync(const uint8_t* aFontData,
                           std::move(messages));
 }
 
-void gfxUserFontEntry::StartPlatformFontLoadOnWorkerThread(
+void gfxUserFontEntry::StartPlatformFontLoadOnBackgroundThread(
     const uint8_t* aFontData, uint32_t aLength,
     nsMainThreadPtrHandle<nsIFontLoadCompleteCallback> aCallback) {
-  MOZ_ASSERT(sFontLoadingThread);
-  MOZ_ASSERT(sFontLoadingThread->IsOnCurrentThread());
+  MOZ_ASSERT(!NS_IsMainThread());
 
   uint32_t saneLen;
   gfxUserFontType fontType;
@@ -921,12 +920,6 @@ void gfxUserFontEntry::FontDataDownloadComplete(
 void gfxUserFontEntry::LoadPlatformFontAsync(
     const uint8_t* aFontData, uint32_t aLength,
     nsIFontLoadCompleteCallback* aCallback) {
-  // Ensure the font loading thread is available.
-  if (!sFontLoadingThread) {
-    sFontLoadingThread =
-        new LazyIdleThread(5000, NS_LITERAL_CSTRING("FontLoader"));
-  }
-
   nsMainThreadPtrHandle<nsIFontLoadCompleteCallback> cb(
       new nsMainThreadPtrHolder<nsIFontLoadCompleteCallback>("FontLoader",
                                                              aCallback));
@@ -943,11 +936,10 @@ void gfxUserFontEntry::LoadPlatformFontAsync(
   nsCOMPtr<nsIRunnable> event =
       NewRunnableMethod<const uint8_t*, uint32_t,
                         nsMainThreadPtrHandle<nsIFontLoadCompleteCallback>>(
-          "gfxUserFontEntry::StartPlatformFontLoadOnWorkerThread", this,
-          &gfxUserFontEntry::StartPlatformFontLoadOnWorkerThread, aFontData,
+          "gfxUserFontEntry::StartPlatformFontLoadOnBackgroundThread", this,
+          &gfxUserFontEntry::StartPlatformFontLoadOnBackgroundThread, aFontData,
           aLength, cb);
-  MOZ_ALWAYS_SUCCEEDS(
-      sFontLoadingThread->Dispatch(event.forget(), NS_DISPATCH_NORMAL));
+  MOZ_ALWAYS_SUCCEEDS(NS_DispatchBackgroundTask(event.forget()));
 }
 
 void gfxUserFontEntry::ContinuePlatformFontLoadOnMainThread(
@@ -1424,8 +1416,6 @@ gfxUserFontSet::UserFontCache::MemoryReporter::CollectReports(
   return NS_OK;
 }
 
-StaticRefPtr<LazyIdleThread> gfxUserFontEntry::sFontLoadingThread;
-
 #ifdef DEBUG_USERFONT_CACHE
 
 void gfxUserFontSet::UserFontCache::Entry::Dump() {
diff --git a/gfx/thebes/gfxUserFontSet.h b/gfx/thebes/gfxUserFontSet.h
index 02f528bc476c..95c5bae5a2d2 100644
--- a/gfx/thebes/gfxUserFontSet.h
+++ b/gfx/thebes/gfxUserFontSet.h
@@ -641,8 +641,6 @@ class gfxUserFontEntry : public gfxFontEntry {
     MOZ_ASSERT_UNREACHABLE("not meaningful for a userfont placeholder");
   }
 
-  static void Shutdown() { sFontLoadingThread = nullptr; }
-
  protected:
   struct OTSMessage {
     nsCString mMessage;
@@ -679,8 +677,8 @@ class gfxUserFontEntry : public gfxFontEntry {
   void LoadPlatformFontAsync(const uint8_t* aFontData, uint32_t aLength,
                              nsIFontLoadCompleteCallback* aCallback);
 
-  // helper method for LoadPlatformFontAsync; runs on the FontLoader thread
-  void StartPlatformFontLoadOnWorkerThread(
+  // helper method for LoadPlatformFontAsync; runs on a background thread
+  void StartPlatformFontLoadOnBackgroundThread(
       const uint8_t* aFontData, uint32_t aLength,
       nsMainThreadPtrHandle<nsIFontLoadCompleteCallback> aCallback);
 
@@ -749,8 +747,6 @@ class gfxUserFontEntry : public gfxFontEntry {
   gfxUserFontSet* MOZ_NON_OWNING_REF
       mFontSet;  // font-set which owns this userfont entry
   RefPtr<gfxFontSrcPrincipal> mPrincipal;
-
-  static mozilla::StaticRefPtr<mozilla::LazyIdleThread> sFontLoadingThread;
 };
 
 #endif /* GFX_USER_FONT_SET_H */
diff --git a/layout/build/nsLayoutStatics.cpp b/layout/build/nsLayoutStatics.cpp
index db0ecd45f9bd..ae7d196ec06f 100644
--- a/layout/build/nsLayoutStatics.cpp
+++ b/layout/build/nsLayoutStatics.cpp
@@ -416,6 +416,4 @@ void nsLayoutStatics::Shutdown() {
   css::ImageLoader::Shutdown();
 
   mozilla::net::UrlClassifierFeatureFactory::Shutdown();
-
-  gfxUserFontEntry::Shutdown();
 }