Bug 753784; add the ability to force a single tile. r=roc

gfx/gl/GLContext.cpp

@@ -916,7 +916,8 @@ TiledTextureImage::TiledTextureImage(GLContext* aGL,
     , mTextureState(Created)
     , mIterationCallback(nsnull)
 {
-    mTileSize = mGL->WantsSmallTiles() ? 256 : mGL->GetMaxTextureSize();
+    mTileSize = (!(aFlags & TextureImage::ForceSingleTile) && mGL->WantsSmallTiles())
+        ? 256 : mGL->GetMaxTextureSize();
     if (aSize != nsIntSize(0,0)) {
         Resize(aSize);
     }

gfx/gl/GLContext.h

@@ -94,7 +94,8 @@ public:
     enum Flags {
         NoFlags          = 0x0,
         UseNearestFilter = 0x1,
-        NeedsYFlip       = 0x2
+        NeedsYFlip       = 0x2,
+        ForceSingleTile  = 0x4
     };
 
     typedef gfxASurface::gfxContentType ContentType;

gfx/layers/ImageLayers.h

@@ -604,10 +604,19 @@ public:
     ComputeEffectiveTransformForMaskLayer(aTransformToSurface);
   }
 
+  /**
+   * if true, the image will only be backed by a single tile texture
+   */
+  void SetForceSingleTile(bool aForceSingleTile)
+  {
+    mForceSingleTile = aForceSingleTile;
+    Mutated();
+  }
+
 protected:
   ImageLayer(LayerManager* aManager, void* aImplData)
     : Layer(aManager, aImplData), mFilter(gfxPattern::FILTER_GOOD)
-    , mScaleMode(SCALE_NONE) {}
+    , mScaleMode(SCALE_NONE), mForceSingleTile(false) {}
 
   virtual nsACString& PrintInfo(nsACString& aTo, const char* aPrefix);
 
@@ -616,6 +625,7 @@ protected:
   gfxPattern::GraphicsFilter mFilter;
   gfxIntSize mScaleToSize;
   ScaleMode mScaleMode;
+  bool mForceSingleTile;
 };
 
 /****** Image subtypes for the different formats ******/

gfx/layers/basic/BasicLayers.cpp

@@ -2546,7 +2546,7 @@ public:
 
   virtual void FillSpecificAttributes(SpecificLayerAttributes& aAttrs)
   {
-    aAttrs = ImageLayerAttributes(mFilter);
+    aAttrs = ImageLayerAttributes(mFilter, mForceSingleTile);
   }
 
   virtual Layer* AsLayer() { return this; }

gfx/layers/ipc/PLayers.ipdl

@@ -94,7 +94,10 @@ struct ThebesLayerAttributes {
 struct ContainerLayerAttributes{ FrameMetrics metrics; };
 struct ColorLayerAttributes    { gfxRGBA color; };
 struct CanvasLayerAttributes   { GraphicsFilterType filter; };
-struct ImageLayerAttributes    { GraphicsFilterType filter; };
+struct ImageLayerAttributes    {
+  GraphicsFilterType filter;
+  bool forceSingleTile;
+};
 
 union SpecificLayerAttributes {
   null_t;

gfx/layers/ipc/ShadowLayersParent.cpp

@@ -253,13 +253,15 @@ ShadowLayersParent::RecvUpdate(const InfallibleTArray<Edit>& cset,
           specific.get_CanvasLayerAttributes().filter());
         break;
 
-      case Specific::TImageLayerAttributes:
+      case Specific::TImageLayerAttributes: {
         MOZ_LAYERS_LOG(("[ParentSide]   image layer"));
 
-        static_cast<ImageLayer*>(layer)->SetFilter(
-          specific.get_ImageLayerAttributes().filter());
+        ImageLayer* imageLayer = static_cast<ImageLayer*>(layer);
+        const ImageLayerAttributes& attrs = specific.get_ImageLayerAttributes();
+        imageLayer->SetFilter(attrs.filter());
+        imageLayer->SetForceSingleTile(attrs.forceSingleTile());
         break;
-
+      }
       default:
         NS_RUNTIMEABORT("not reached");
       }

gfx/layers/opengl/ImageLayerOGL.cpp

@@ -660,7 +660,10 @@ ShadowImageLayerOGL::Init(const SharedImage& aFront)
     mSize = surf->GetSize();
     mTexImage = gl()->CreateTextureImage(nsIntSize(mSize.width, mSize.height),
                                          surf->GetContentType(),
-                                         LOCAL_GL_CLAMP_TO_EDGE);
+                                         LOCAL_GL_CLAMP_TO_EDGE,
+                                         mForceSingleTile
+                                          ? TextureImage::ForceSingleTile
+                                          : TextureImage::NoFlags);
     return true;
   } else {
     YUVImage yuv = aFront.get_YUVImage();

layout/base/FrameLayerBuilder.cpp

@@ -885,6 +885,7 @@ ContainerState::CreateOrRecycleMaskImageLayerFor(Layer* aLayer)
     if (!result)
       return nsnull;
     result->SetUserData(&gMaskLayerUserData, new MaskLayerUserData());
+    result->SetForceSingleTile(true);
   }
   
   return result.forget();