Bug 858969 - Refactor dynamic toolbar so page is offset and not overlapped. r=kats,nrc

Refactor the dynamic toolbar code so that the ownership of various properties
is clearer, and the page is offset by the toolbar instead of being overlapped.
This fixes problems with the scroll origin of the page not corresponding to
the visible origin on the screen.

Author: Cwiiis

gfx/layers/Compositor.h

@@ -252,6 +252,12 @@ class Compositor : public RefCounted<Compositor>
    */
   virtual void SetDestinationSurfaceSize(const gfx::IntSize& aSize) = 0;
 
+  /**
+   * Declare an offset to use when rendering layers. This will be ignored when
+   * rendering to a target instead of the screen.
+   */
+  virtual void SetScreenRenderOffset(const gfx::Point& aOffset) = 0;
+
   /**
    * Tell the compositor to actually draw a quad. What to do draw and how it is
    * drawn is specified by aEffectChain. aRect is the quad to draw, in user space.

gfx/layers/ipc/CompositorParent.cpp

@@ -885,7 +885,7 @@ CompositorParent::TransformScrollableLayer(Layer* aLayer, const gfx3DMatrix& aRo
   const FrameMetrics& metrics = container->GetFrameMetrics();
   // We must apply the resolution scale before a pan/zoom transform, so we call
   // GetTransform here.
-  const gfx3DMatrix& currentTransform = aLayer->GetTransform();
+  gfx3DMatrix currentTransform = aLayer->GetTransform();
 
   gfx3DMatrix treeTransform;
 
@@ -934,10 +934,15 @@ CompositorParent::TransformScrollableLayer(Layer* aLayer, const gfx3DMatrix& aRo
   displayPortDevPixels.y += scrollOffsetDevPixels.y;
 
   gfx::Margin fixedLayerMargins(0, 0, 0, 0);
+  float offsetX = 0, offsetY = 0;
   SyncViewportInfo(displayPortDevPixels, 1/rootScaleX, mLayersUpdated,
-                   mScrollOffset, mXScale, mYScale, fixedLayerMargins);
+                   mScrollOffset, mXScale, mYScale, fixedLayerMargins,
+                   offsetX, offsetY);
   mLayersUpdated = false;
 
+  // Apply the render offset
+  mLayerManager->GetCompositor()->SetScreenRenderOffset(gfx::Point(offsetX, offsetY));
+
   // Handle transformations for asynchronous panning and zooming. We determine the
   // zoom used by Gecko from the transformation set on the root layer, and we
   // determine the scroll offset used by Gecko from the frame metrics of the
@@ -1091,11 +1096,13 @@ void
 CompositorParent::SyncViewportInfo(const nsIntRect& aDisplayPort,
                                    float aDisplayResolution, bool aLayersUpdated,
                                    nsIntPoint& aScrollOffset, float& aScaleX, float& aScaleY,
-                                   gfx::Margin& aFixedLayerMargins)
+                                   gfx::Margin& aFixedLayerMargins, float& aOffsetX,
+                                   float& aOffsetY)
 {
 #ifdef MOZ_WIDGET_ANDROID
   AndroidBridge::Bridge()->SyncViewportInfo(aDisplayPort, aDisplayResolution, aLayersUpdated,
-                                            aScrollOffset, aScaleX, aScaleY, aFixedLayerMargins);
+                                            aScrollOffset, aScaleX, aScaleY, aFixedLayerMargins,
+                                            aOffsetX, aOffsetY);
 #endif
 }
 

gfx/layers/ipc/CompositorParent.h

@@ -180,7 +180,7 @@ class CompositorParent : public PCompositorParent,
   virtual void SetPageRect(const gfx::Rect& aCssPageRect);
   virtual void SyncViewportInfo(const nsIntRect& aDisplayPort, float aDisplayResolution, bool aLayersUpdated,
                                 nsIntPoint& aScrollOffset, float& aScaleX, float& aScaleY,
-                                gfx::Margin& aFixedLayerMargins);
+                                gfx::Margin& aFixedLayerMargins, float& aOffsetX, float& aOffsetY);
   void SetEGLSurfaceSize(int width, int height);
 
 private:

gfx/layers/opengl/CompositorOGL.cpp

@@ -621,6 +621,9 @@ CompositorOGL::PrepareViewport(const gfx::IntSize& aSize,
   viewMatrix.Translate(-gfxPoint(1.0, -1.0));
   viewMatrix.Scale(2.0f / float(aSize.width), 2.0f / float(aSize.height));
   viewMatrix.Scale(1.0f, -1.0f);
+  if (!mTarget) {
+    viewMatrix.Translate(gfxPoint(mRenderOffset.x, mRenderOffset.y));
+  }
 
   viewMatrix = aWorldTransform * viewMatrix;
 

gfx/layers/opengl/CompositorOGL.h

@@ -90,6 +90,10 @@ class CompositorOGL : public Compositor
    */
   virtual void SetDestinationSurfaceSize(const gfx::IntSize& aSize) MOZ_OVERRIDE;
 
+  virtual void SetScreenRenderOffset(const gfx::Point& aOffset) MOZ_OVERRIDE {
+    mRenderOffset = aOffset;
+  }
+
   virtual void MakeCurrent(MakeCurrentFlags aFlags = 0) MOZ_OVERRIDE {
     if (mDestroyed) {
       NS_WARNING("Call on destroyed layer manager");
@@ -141,6 +145,8 @@ class CompositorOGL : public Compositor
   /** The size of the surface we are rendering to */
   nsIntSize mSurfaceSize;
 
+  gfx::Point mRenderOffset;
+
   /** Helper-class used by Initialize **/
   class ReadDrawFPSPref MOZ_FINAL : public nsRunnable {
   public: