Backed out changeset ca73b950e612 (bug 1134762) for B2G crashtest failures.

gfx/layers/client/ClientTiledPaintedLayer.cpp

@@ -219,12 +219,6 @@ ClientTiledPaintedLayer::IsScrollingOnCompositor(const FrameMetrics& aParentMetr
 bool
 ClientTiledPaintedLayer::UseFastPath()
 {
-  // The fast path doesn't allow rendering at low resolution. It will draw the low-res
-  // area at full resolution and cause OOM.
-  if (gfxPrefs::UseLowPrecisionBuffer()) {
-    return false;
-  }
-
   LayerMetricsWrapper scrollAncestor;
   GetAncestorLayers(&scrollAncestor, nullptr);
   if (!scrollAncestor) {
@@ -233,35 +227,16 @@ ClientTiledPaintedLayer::UseFastPath()
   const FrameMetrics& parentMetrics = scrollAncestor.Metrics();
 
   bool multipleTransactionsNeeded = gfxPlatform::GetPlatform()->UseProgressivePaint()
+                                 || gfxPrefs::UseLowPrecisionBuffer()
                                  || !parentMetrics.GetCriticalDisplayPort().IsEmpty();
   bool isFixed = GetIsFixedPosition() || GetParent()->GetIsFixedPosition();
   bool isScrollable = parentMetrics.IsScrollable();
 
-  return !multipleTransactionsNeeded || isFixed || !isScrollable;
-}
-
-bool
-ClientTiledPaintedLayer::UseProgressiveDraw() {
-  // Don't draw progressively in a reftest scenario (that's what the HasShadowTarget() check is for).
-  if (!gfxPlatform::GetPlatform()->UseProgressivePaint() || ClientManager()->HasShadowTarget()) {
-    return false;
-  }
-
-  // XXX We probably want to disable progressive drawing for non active APZ layers in the future
-  //     but we should wait for a proper test case before making this change.
-
-#if 0 //!defined(MOZ_WIDGET_ANDROID) || defined(MOZ_ANDROID_APZ)
-  LayerMetricsWrapper scrollAncestor;
-  GetAncestorLayers(&scrollAncestor, nullptr);
-  if (!scrollAncestor) {
-    return true;
-  }
-  const FrameMetrics& parentMetrics = scrollAncestor.Metrics();
-
-  return !IsScrollingOnCompositor(parentMetrics);
-#else
-  return true;
+  return !multipleTransactionsNeeded || isFixed || !isScrollable
+#if !defined(MOZ_WIDGET_ANDROID) || defined(MOZ_ANDROID_APZ)
+         || !IsScrollingOnCompositor(parentMetrics)
 #endif
+         ;
 }
 
 bool
@@ -276,8 +251,10 @@ ClientTiledPaintedLayer::RenderHighPrecision(nsIntRegion& aInvalidRegion,
     return false;
   }
 
-  // Only draw progressively when the resolution is unchanged
-  if (UseProgressiveDraw() &&
+  // Only draw progressively when the resolution is unchanged, and we're not
+  // in a reftest scenario (that's what the HasShadowManager() check is for).
+  if (gfxPlatform::GetPlatform()->UseProgressivePaint() &&
+      !ClientManager()->HasShadowTarget() &&
       mContentClient->mTiledBuffer.GetFrameResolution() == mPaintData.mResolution) {
     // Store the old valid region, then clear it before painting.
     // We clip the old valid region to the visible region, as it only gets
@@ -441,16 +418,6 @@ ClientTiledPaintedLayer::RenderLayer()
       ToClientLayer(GetMaskLayer())->RenderLayer();
     }
 
-    // In some cases we can take a fast path and just be done with it.
-    if (UseFastPath()) {
-      TILING_LOG("TILING %p: Taking fast-path\n", this);
-      mValidRegion = neededRegion;
-      mContentClient->mTiledBuffer.PaintThebes(mValidRegion, invalidRegion, callback, data);
-      ClientManager()->Hold(this);
-      mContentClient->UseTiledLayerBuffer(TiledContentClient::TILED_BUFFER);
-      return;
-    }
-
     // For more complex cases we need to calculate a bunch of metrics before we
     // can do the paint.
     BeginPaint();
@@ -458,6 +425,32 @@ ClientTiledPaintedLayer::RenderLayer()
       return;
     }
 
+    // In some cases we can take a fast path and just be done with it.
+    if (UseFastPath()) {
+      TILING_LOG("TILING %p: Taking fast-path\n", this);
+      mValidRegion = neededRegion;
+
+      // Make sure that tiles that fall outside of the visible region or outside of the
+      // critical displayport are discarded on the first update. Also make sure that we
+      // only draw stuff inside the critical displayport on the first update.
+      if (!mPaintData.mCriticalDisplayPort.IsEmpty()) {
+        mValidRegion.And(mValidRegion, LayerIntRect::ToUntyped(mPaintData.mCriticalDisplayPort));
+        invalidRegion.And(invalidRegion, LayerIntRect::ToUntyped(mPaintData.mCriticalDisplayPort));
+      }
+
+      if (invalidRegion.IsEmpty()) {
+        EndPaint();
+        return;
+      }
+
+      mContentClient->mTiledBuffer.SetFrameResolution(mPaintData.mResolution);
+      mContentClient->mTiledBuffer.PaintThebes(mValidRegion, invalidRegion, callback, data);
+      ClientManager()->Hold(this);
+      mContentClient->UseTiledLayerBuffer(TiledContentClient::TILED_BUFFER);
+      EndPaint();
+      return;
+    }
+
     // Make sure that tiles that fall outside of the visible region or outside of the
     // critical displayport are discarded on the first update. Also make sure that we
     // only draw stuff inside the critical displayport on the first update.

gfx/layers/client/ClientTiledPaintedLayer.h

@@ -106,13 +106,6 @@ private:
    */
   bool IsScrollingOnCompositor(const FrameMetrics& aParentMetrics);
 
-  /**
-   * Check if we should use progressive draw on this layer. We will
-   * disable progressive draw based on a preference or if the layer
-   * is not being scrolled.
-   */
-  bool UseProgressiveDraw();
-
   /**
    * Helper function to do the high-precision paint.
    * This function returns true if it updated the paint buffer.