From cd3cc3e99f33df97f21be6d60f242b5f5a31388b Mon Sep 17 00:00:00 2001
From: Matt Woodrow <mwoodrow@mozilla.com>
Date: Wed, 29 Jul 2015 12:01:21 -0400
Subject: [PATCH] Bug 1180326 - Part 2: Add support for variable tile sizes.
 r=jrmuizel

---
 gfx/layers/TiledLayerBuffer.h             | 3 ++-
 gfx/layers/client/TiledContentClient.cpp  | 1 +
 gfx/layers/composite/TiledContentHost.cpp | 5 ++++-
 gfx/layers/ipc/LayersMessages.ipdlh       | 2 ++
 4 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/gfx/layers/TiledLayerBuffer.h b/gfx/layers/TiledLayerBuffer.h
index 1c741184f35..7d764a9640a 100644
--- a/gfx/layers/TiledLayerBuffer.h
+++ b/gfx/layers/TiledLayerBuffer.h
@@ -150,7 +150,7 @@ public:
   gfx::IntPoint GetTileOffset(TileIntPoint aPosition) const {
     gfx::IntSize scaledTileSize = GetScaledTileSize();
     return gfx::IntPoint(aPosition.x * scaledTileSize.width,
-                         aPosition.y * scaledTileSize.height);
+                         aPosition.y * scaledTileSize.height) + mTileOrigin;
   }
 
   const TilesPlacement& GetPlacement() const { return mTiles; }
@@ -194,6 +194,7 @@ protected:
   TilesPlacement  mTiles;
   float           mResolution;
   gfx::IntSize    mTileSize;
+  gfx::IntPoint   mTileOrigin;
 };
 
 template<typename Derived, typename Tile> void
diff --git a/gfx/layers/client/TiledContentClient.cpp b/gfx/layers/client/TiledContentClient.cpp
index 9630746f3d5..1620ecc66c5 100644
--- a/gfx/layers/client/TiledContentClient.cpp
+++ b/gfx/layers/client/TiledContentClient.cpp
@@ -868,6 +868,7 @@ ClientMultiTiledLayerBuffer::GetSurfaceDescriptorTiles()
   }
   return SurfaceDescriptorTiles(mValidRegion,
                                 tiles,
+                                mTileOrigin, mTileSize,
                                 mTiles.mFirst.x, mTiles.mFirst.y,
                                 mTiles.mSize.width, mTiles.mSize.height,
                                 mResolution, mFrameResolution.xScale,
diff --git a/gfx/layers/composite/TiledContentHost.cpp b/gfx/layers/composite/TiledContentHost.cpp
index a1ddf29ca4d..567bd37f6c6 100644
--- a/gfx/layers/composite/TiledContentHost.cpp
+++ b/gfx/layers/composite/TiledContentHost.cpp
@@ -242,7 +242,8 @@ TiledLayerBufferComposite::UseTiles(const SurfaceDescriptorTiles& aTiles,
                                     Compositor* aCompositor,
                                     ISurfaceAllocator* aAllocator)
 {
-  if (mResolution != aTiles.resolution()) {
+  if (mResolution != aTiles.resolution() ||
+      aTiles.tileSize() != mTileSize) {
     Clear();
   }
   MOZ_ASSERT(aAllocator);
@@ -352,6 +353,8 @@ TiledLayerBufferComposite::UseTiles(const SurfaceDescriptorTiles& aTiles,
   }
 
   mTiles = newTiles;
+  mTileSize = aTiles.tileSize();
+  mTileOrigin = aTiles.tileOrigin();
   mValidRegion = aTiles.validRegion();
   mResolution = aTiles.resolution();
   mFrameResolution = CSSToParentLayerScale2D(aTiles.frameXResolution(),
diff --git a/gfx/layers/ipc/LayersMessages.ipdlh b/gfx/layers/ipc/LayersMessages.ipdlh
index 9e4590df046..ce75d526cb9 100644
--- a/gfx/layers/ipc/LayersMessages.ipdlh
+++ b/gfx/layers/ipc/LayersMessages.ipdlh
@@ -333,6 +333,8 @@ union TileDescriptor {
 struct SurfaceDescriptorTiles {
   nsIntRegion validRegion;
   TileDescriptor[] tiles;
+  IntPoint    tileOrigin;
+  IntSize     tileSize;
   int         firstTileX;
   int         firstTileY;
   int         retainedWidth;