Bug 824428 - Add Environment option which would allow to use Tiled Thebes Layers. r=bgirard

gfx/layers/Layers.cpp

@@ -260,6 +260,13 @@ LayerManager::GetScrollableLayers(nsTArray<Layer*>& aArray)
   }
 }
 
+bool ThebesLayer::UseTiledThebes()
+{
+  static bool useTiledThebesLayer =
+    Preferences::GetBool("gfx.use_tiled_thebes", false);
+  return useTiledThebesLayer;
+}
+
 already_AddRefed<gfxASurface>
 LayerManager::CreateOptimalSurface(const gfxIntSize &aSize,
                                    gfxASurface::gfxImageFormat aFormat)

gfx/layers/Layers.h

@@ -1248,6 +1248,8 @@ public:
    */
   gfxPoint GetResidualTranslation() const { return mResidualTranslation; }
 
+  static bool UseTiledThebes();
+
 protected:
   ThebesLayer(LayerManager* aManager, void* aImplData)
     : Layer(aManager, aImplData)

gfx/layers/TiledLayerBuffer.h

@@ -8,11 +8,6 @@
 #define TILEDLAYERBUFFER_TILE_SIZE 256
 
 // Debug defines
-#ifdef MOZ_ANDROID_OMTC
-  // This needs to go away as we enabled tiled
-  // layers everywhere.
-  #define FORCE_BASICTILEDTHEBESLAYER
-#endif
 //#define GFX_TILEDLAYER_DEBUG_OVERLAY
 //#define GFX_TILEDLAYER_PREF_WARNINGS
 

gfx/layers/basic/BasicLayerManager.cpp

@@ -1341,8 +1341,8 @@ already_AddRefed<ThebesLayer>
 BasicShadowLayerManager::CreateThebesLayer()
 {
   NS_ASSERTION(InConstruction(), "Only allowed in construction phase");
-#ifdef FORCE_BASICTILEDTHEBESLAYER
-  if (HasShadowManager() && GetParentBackendType() == LAYERS_OPENGL) {
+  if (HasShadowManager() && GetParentBackendType() == LAYERS_OPENGL &&
+      ThebesLayer::UseTiledThebes()) {
     // BasicTiledThebesLayer doesn't support main
     // thread compositing so only return this layer
     // type if we have a shadow manager.
@@ -1351,7 +1351,6 @@ BasicShadowLayerManager::CreateThebesLayer()
     MAYBE_CREATE_SHADOW(Thebes);
     return layer.forget();
   } else
-#endif
   {
     nsRefPtr<BasicShadowableThebesLayer> layer =
       new BasicShadowableThebesLayer(this);

gfx/layers/opengl/LayerManagerOGL.cpp

@@ -1553,11 +1553,9 @@ LayerManagerOGL::CreateShadowThebesLayer()
     NS_WARNING("Call on destroyed layer manager");
     return nullptr;
   }
-#ifdef FORCE_BASICTILEDTHEBESLAYER
-  return nsRefPtr<ShadowThebesLayer>(new TiledThebesLayerOGL(this)).forget();
-#else
+  if (ThebesLayer::UseTiledThebes())
+    return nsRefPtr<ShadowThebesLayer>(new TiledThebesLayerOGL(this)).forget();
   return nsRefPtr<ShadowThebesLayerOGL>(new ShadowThebesLayerOGL(this)).forget();
-#endif
 }
 
 already_AddRefed<ShadowContainerLayer>

gfx/layers/opengl/ThebesLayerOGL.cpp

@@ -1027,9 +1027,8 @@ ShadowThebesLayerOGL::ShadowThebesLayerOGL(LayerManagerOGL *aManager)
   : ShadowThebesLayer(aManager, nullptr)
   , LayerOGL(aManager)
 {
-#ifdef FORCE_BASICTILEDTHEBESLAYER
-  NS_ABORT();
-#endif
+  if (ThebesLayer::UseTiledThebes())
+    NS_ABORT();
   mImplData = static_cast<LayerOGL*>(this);
 }
 

mobile/android/app/mobile.js

@@ -671,3 +671,6 @@ pref("app.orientation.default", "");
 // On memory pressure, release dirty but unused pages held by jemalloc
 // back to the system.
 pref("memory.free_dirty_pages", true);
+
+// Enable tiled layers rendering by default on android
+pref("gfx.use_tiled_thebes", true);