Backed out changeset 5368aced79b3 (bug 814437) because it breaks Android builds

gfx/layers/Layers.h

@@ -1148,6 +1148,7 @@ public:
    * Can be used anytime
    */
   const nsIntRegion& GetValidRegion() const { return mValidRegion; }
+  virtual const nsIntRegion& GetValidLowPrecisionRegion() const { return mValidRegion; }
 
   virtual ThebesLayer* AsThebesLayer() { return this; }
 

gfx/layers/TiledLayerBuffer.h

@@ -191,12 +191,6 @@ public:
   virtual void PaintedTiledLayerBuffer(const BasicTiledLayerBuffer* aTiledBuffer) = 0;
 
   virtual void MemoryPressure() = 0;
-
-  /**
-   * If some part of the buffer is being rendered at a lower precision, this
-   * returns that region. If it is not, an empty region will be returned.
-   */
-  virtual const nsIntRegion& GetValidLowPrecisionRegion() const = 0;
 };
 
 // Normal integer division truncates towards zero,

gfx/layers/opengl/LayerManagerOGL.cpp

@@ -1684,26 +1684,13 @@ LayerManagerOGL::ComputeRenderIntegrityInternal(Layer* aLayer,
     SubtractTransformedRegion(aScreenRegion, incompleteRegion, transformToScreen);
 
     // See if there's any incomplete low-precision rendering
-    TiledLayerComposer* composer = nullptr;
-    ShadowLayer* shadow = aLayer->AsShadowLayer();
-    if (shadow) {
-      composer = shadow->AsTiledLayerComposer();
-      if (composer) {
-        incompleteRegion.Sub(incompleteRegion, composer->GetValidLowPrecisionRegion());
+    incompleteRegion.Sub(incompleteRegion, thebesLayer->GetValidLowPrecisionRegion());
     if (!incompleteRegion.IsEmpty()) {
       SubtractTransformedRegion(aLowPrecisionScreenRegion, incompleteRegion, transformToScreen);
     }
   }
 }
 
-    // If we can't get a valid low precision region, assume it's the same as
-    // the high precision region.
-    if (!composer) {
-      SubtractTransformedRegion(aLowPrecisionScreenRegion, incompleteRegion, transformToScreen);
-    }
-  }
-}
-
 static int
 GetRegionArea(const nsIntRegion& aRegion)
 {
@@ -1761,6 +1748,7 @@ LayerManagerOGL::ComputeRenderIntegrity()
 #ifdef MOZ_ANDROID_OMTC
   // Use the transform on the primary scrollable layer and its FrameMetrics
   // to find out how much of the viewport the current displayport covers
+  bool hasLowPrecision = true;
   Layer* primaryScrollable = GetPrimaryScrollableLayer();
   if (primaryScrollable) {
     // This is derived from the code in
@@ -1780,39 +1768,17 @@ LayerManagerOGL::ComputeRenderIntegrity()
         GetDisplayportCoverage(metrics.mCriticalDisplayPort, transform, screenRect);
     }
 
-    // Clip the screen rect to the document bounds
-    gfxRect documentBounds =
-      transform.TransformBounds(gfxRect(metrics.mScrollableRect.x - metrics.mScrollOffset.x,
-                                        metrics.mScrollableRect.y - metrics.mScrollOffset.y,
-                                        metrics.mScrollableRect.width,
-                                        metrics.mScrollableRect.height));
-    documentBounds.RoundOut();
-    screenRect = screenRect.Intersect(nsIntRect(documentBounds.x, documentBounds.y,
-                                                documentBounds.width, documentBounds.height));
-
-    // If the screen rect is empty, the user has scrolled entirely into
-    // over-scroll and so we can be considered to have full integrity.
-    if (screenRect.IsEmpty()) {
-      return 1.0f;
-    }
-
     // Work out how much of the display-port covers the screen
-    bool hasLowPrecision = false;
     if (!metrics.mDisplayPort.IsEmpty()) {
       if (hasLowPrecision) {
         lowPrecisionMultiplier =
           GetDisplayportCoverage(metrics.mDisplayPort, transform, screenRect);
       } else {
-        lowPrecisionMultiplier = highPrecisionMultiplier =
+        highPrecisionMultiplier =
           GetDisplayportCoverage(metrics.mDisplayPort, transform, screenRect);
       }
     }
   }
-
-  // If none of the screen is covered, we have zero integrity.
-  if (highPrecisionMultiplier <= 0.0f && lowPrecisionMultiplier <= 0.0f) {
-    return 0.0f;
-  }
 #endif // MOZ_ANDROID_OMTC
 
   nsIntRegion screenRegion(screenRect);
@@ -1832,7 +1798,7 @@ LayerManagerOGL::ComputeRenderIntegrity()
     }
 
     return ((highPrecisionIntegrity * highPrecisionMultiplier) +
-            (lowPrecisionIntegrity * lowPrecisionMultiplier)) / 2;
+            (lowPrecisionIntegrity * lowPrecisionMultiplier)) / 2.f;
   }
 
   return 1.f;

gfx/layers/opengl/TiledThebesLayerOGL.h

@@ -113,6 +113,9 @@ public:
   TiledThebesLayerOGL(LayerManagerOGL *aManager);
   virtual ~TiledThebesLayerOGL();
 
+  // Layer implementation
+  const nsIntRegion& GetValidLowPrecisionRegion() const { return mLowPrecisionVideoMemoryTiledBuffer.GetValidRegion(); }
+
   // LayerOGL impl
   void Destroy() {}
   Layer* GetLayer() { return this; }
@@ -132,7 +135,6 @@ public:
   void PaintedTiledLayerBuffer(const BasicTiledLayerBuffer* mTiledBuffer);
   void ProcessUploadQueue();
   void ProcessLowPrecisionUploadQueue();
-  const nsIntRegion& GetValidLowPrecisionRegion() const { return mLowPrecisionVideoMemoryTiledBuffer.GetValidRegion(); }
 
   void MemoryPressure();