Don't hardcode ContentHostTexture in PaintedLayerMLGPU. (bug 1420674 part 1, r=rhunt)

gfx/layers/composite/CompositableHost.h

@@ -46,6 +46,7 @@ class ThebesBufferData;
 class TiledContentHost;
 class CompositableParentManager;
 class WebRenderImageHost;
+class ContentHost;
 class ContentHostTexture;
 struct EffectChain;
 
@@ -149,6 +150,7 @@ public:
   Layer* GetLayer() const { return mLayer; }
   void SetLayer(Layer* aLayer) { mLayer = aLayer; }
 
+  virtual ContentHost* AsContentHost() { return nullptr; }
   virtual ContentHostTexture* AsContentHostTexture() { return nullptr; }
   virtual ImageHost* AsImageHost() { return nullptr; }
   virtual TiledContentHost* AsTiledContentHost() { return nullptr; }

gfx/layers/composite/ContentHost.h

@@ -68,6 +68,7 @@ public:
     MOZ_ASSERT_UNREACHABLE("Must be implemented in derived class");
     return gfx::IntRect();
   }
+  virtual ContentHost* AsContentHost() { return this; }
 
 protected:
   explicit ContentHost(const TextureInfo& aTextureInfo)

gfx/layers/mlgpu/PaintedLayerMLGPU.cpp

@@ -36,11 +36,17 @@ PaintedLayerMLGPU::OnPrepareToRender(FrameBuilder* aBuilder)
     return false;
   }
 
-  mTexture = mHost->AcquireTextureSource();
+  ContentHostTexture* single = mHost->AsContentHostTexture();
+  if (!single) {
+    return false;
+  }
+
+  mTexture = single->AcquireTextureSource();
   if (!mTexture) {
     return false;
   }
-  mTextureOnWhite = mHost->AcquireTextureSourceOnWhite();
+  mTextureOnWhite = single->AcquireTextureSourceOnWhite();
+  mDestOrigin = single->GetOriginOffset();
   return true;
 }
 
@@ -77,9 +83,10 @@ bool
 PaintedLayerMLGPU::SetCompositableHost(CompositableHost* aHost)
 {
   switch (aHost->GetType()) {
+    case CompositableType::CONTENT_TILED:
     case CompositableType::CONTENT_SINGLE:
     case CompositableType::CONTENT_DOUBLE:
-      mHost = static_cast<ContentHostBase*>(aHost)->AsContentHostTexture();
+      mHost = aHost->AsContentHost();
       if (!mHost) {
         gfxWarning() << "ContentHostBase is not a ContentHostTexture";
       }
@@ -95,6 +102,12 @@ PaintedLayerMLGPU::GetCompositableHost()
   return mHost;
 }
 
+gfx::Point
+PaintedLayerMLGPU::GetDestOrigin() const
+{
+  return mDestOrigin;
+}
+
 void
 PaintedLayerMLGPU::CleanupResources()
 {

gfx/layers/mlgpu/PaintedLayerMLGPU.h

@@ -48,9 +48,8 @@ public:
     MOZ_ASSERT(HasComponentAlpha());
     return mTextureOnWhite;
   }
-  ContentHostTexture* GetContentHost() const {
-    return mHost;
-  }
+  gfx::Point GetDestOrigin() const;
+
   SamplerMode GetSamplerMode() {
     // Note that when resamping, we must break the texture coordinates into
     // no-repeat rects. When we have simple integer translations we can
@@ -78,12 +77,13 @@ protected:
   void CleanupResources();
 
 private:
-  RefPtr<ContentHostTexture> mHost;
+  RefPtr<ContentHost> mHost;
   RefPtr<TextureSource> mTexture;
   RefPtr<TextureSource> mTextureOnWhite;
 #ifndef MOZ_IGNORE_PAINT_WILL_RESAMPLE
   LayerIntRegion mDrawRects;
 #endif
+  IntPoint mDestOrigin;
 };
 
 } // namespace layers

gfx/layers/mlgpu/RenderPassMLGPU.cpp

@@ -457,7 +457,7 @@ TexturedRenderPass::TexturedRenderPass(FrameBuilder* aBuilder, const ItemInfo& a
 TexturedRenderPass::Info::Info(const ItemInfo& aItem, PaintedLayerMLGPU* aLayer)
  : item(aItem),
    textureSize(aLayer->GetTexture()->GetSize()),
-   destOrigin(aLayer->GetContentHost()->GetOriginOffset()),
+   destOrigin(aLayer->GetDestOrigin()),
    decomposeIntoNoRepeatRects(aLayer->MayResample())
 {
 }