Bug 1125422 - Add a flag on ContainerLayer to indicate when the entire subtree of layers needs to be in the dispatch-to-content region. r=roc

gfx/layers/Layers.cpp

@@ -924,7 +924,8 @@ ContainerLayer::ContainerLayer(LayerManager* aManager, void* aImplData)
     mUseIntermediateSurface(false),
     mSupportsComponentAlphaChildren(false),
     mMayHaveReadbackChild(false),
-    mChildrenChanged(false)
+    mChildrenChanged(false),
+    mForceDispatchToContentRegion(false)
 {
   mContentFlags = 0; // Clear NO_TEXT, NO_TEXT_OVER_TRANSPARENT
 }
@@ -1081,6 +1082,7 @@ ContainerLayer::FillSpecificAttributes(SpecificLayerAttributes& aAttrs)
   aAttrs = ContainerLayerAttributes(mPreXScale, mPreYScale,
                                     mInheritedXScale, mInheritedYScale,
                                     mPresShellResolution, mScaleToResolution,
+                                    mForceDispatchToContentRegion,
                                     reinterpret_cast<uint64_t>(mHMDInfo.get()));
 }
 
@@ -1748,6 +1750,9 @@ ContainerLayer::PrintInfo(std::stringstream& aStream, const char* aPrefix)
   if (mScaleToResolution) {
     aStream << nsPrintfCString(" [presShellResolution=%g]", mPresShellResolution).get();
   }
+  if (mForceDispatchToContentRegion) {
+    aStream << " [force-dtc]";
+  }
   if (mHMDInfo) {
     aStream << nsPrintfCString(" [hmd=%p]", mHMDInfo.get()).get();
   }

gfx/layers/Layers.h

@@ -916,6 +916,10 @@ public:
    * outside the dispatch-to-content region, we can initiate a gesture without
    * consulting the content thread. Otherwise we must dispatch the event to
    * content.
+   * Note that if a layer or any ancestor layer returns true for
+   * GetForceDispatchToContentRegion() then we must treat the dispatch-to-content
+   * region as encompassing the hit region, and therefore must consult the
+   * content thread before initiating a gesture.
    */
   /**
    * CONSTRUCTION PHASE ONLY
@@ -1967,6 +1971,20 @@ public:
     mChildrenChanged = aVal;
   }
 
+  void SetForceDispatchToContentRegion(bool aVal) {
+    if (mForceDispatchToContentRegion == aVal) {
+      return;
+    }
+
+    MOZ_LAYERS_LOG_IF_SHADOWABLE(this, ("Layer::Mutated(%p) ForceDispatchToContentRegion", this));
+    mForceDispatchToContentRegion = aVal;
+    Mutated();
+  }
+
+  bool GetForceDispatchToContentRegion() const {
+    return mForceDispatchToContentRegion;
+  }
+
   /**
    * VR
    */
@@ -2023,6 +2041,7 @@ protected:
   // This is updated by ComputeDifferences. This will be true if we need to invalidate
   // the intermediate surface.
   bool mChildrenChanged;
+  bool mForceDispatchToContentRegion;
   nsRefPtr<gfx::VRHMDInfo> mHMDInfo;
 };
 

gfx/layers/ipc/LayerTransactionParent.cpp

@@ -386,6 +386,7 @@ LayerTransactionParent::RecvUpdate(InfallibleTArray<Edit>&& cset,
         containerLayer->SetInheritedScale(attrs.inheritedXScale(), attrs.inheritedYScale());
         containerLayer->SetScaleToResolution(attrs.scaleToResolution(),
                                              attrs.presShellResolution());
+        containerLayer->SetForceDispatchToContentRegion(attrs.forceDispatchToContentRegion());
 
         if (attrs.hmdInfo()) {
           if (!IsSameProcess()) {

gfx/layers/ipc/LayersMessages.ipdlh

@@ -234,6 +234,7 @@ struct ContainerLayerAttributes {
   float inheritedYScale;
   float presShellResolution;
   bool scaleToResolution;
+  bool forceDispatchToContentRegion;
   // This is a bare pointer; LayerTransactionParent::RecvUpdate prevents this
   // from being used when !IsSameProcess(), but we should make this truly
   // cross process at some point by passing the HMDConfig