Bug 1234485 - Part 2. Implement nsSVGIntegrationUtils::IsMaskResourceReady. r=mstange

We need this new function to determine whether paint mask onto mask layer.
MozReview-Commit-ID: IeEamPi9S8v

--HG--
extra : rebase_source : 993ae4bbe31c2c21704813c318f5328719194930

layout/svg/nsSVGIntegrationUtils.cpp

@@ -723,6 +723,32 @@ nsSVGIntegrationUtils::DetermineMaskUsage(nsIFrame* aFrame,
   }
 }
 
+bool
+nsSVGIntegrationUtils::IsMaskResourceReady(nsIFrame* aFrame)
+{
+  nsIFrame* firstFrame =
+    nsLayoutUtils::FirstContinuationOrIBSplitSibling(aFrame);
+  nsSVGEffects::EffectProperties effectProperties =
+    nsSVGEffects::GetEffectProperties(firstFrame);
+  nsTArray<nsSVGMaskFrame*> maskFrames = effectProperties.GetMaskFrames();
+  const nsStyleSVGReset* svgReset = firstFrame->StyleSVGReset();
+
+  for (uint32_t i = 0; i < maskFrames.Length(); i++) {
+    // Refers to a valid SVG mask.
+    if (maskFrames[i]) {
+      continue;
+    }
+
+    // Refers to an external resource, which is not ready yet.
+    if (!svgReset->mMask.mLayers[i].mImage.IsComplete()) {
+      return false;
+    }
+  }
+
+  // Either all mask resources are ready, or no mask resource is needed.
+  return true;
+}
+
 DrawResult
 nsSVGIntegrationUtils::PaintMaskAndClipPath(const PaintFramesParams& aParams)
 {

layout/svg/nsSVGIntegrationUtils.h

@@ -176,6 +176,12 @@ public:
   static void
   DetermineMaskUsage(nsIFrame* aFrame, bool aHandleOpacity, MaskUsage& aUsage);
 
+  /**
+   * Return true if all the mask resource of aFrame are ready.
+   */
+  static bool
+  IsMaskResourceReady(nsIFrame* aFrame);
+
   /**
    * Paint non-SVG frame with filter and opacity effect.
    */