Bug 967844. Part 2: Move mContentDescription from Layer to FrameMetrics. r=kats

--HG--
extra : rebase_source : d5a2d8ea13369db215e96e721efc3ce0b354a523

gfx/ipc/GfxMessageUtils.h

@@ -754,6 +754,17 @@ struct ParamTraits<mozilla::layers::FrameMetrics>
     WriteParam(aMsg, aParam.mScrollGeneration);
     WriteParam(aMsg, aParam.mTransformScale);
     WriteParam(aMsg, aParam.mBackgroundColor);
+    WriteParam(aMsg, aParam.GetContentDescription());
+  }
+
+  static bool ReadContentDescription(const Message* aMsg, void** aIter, paramType* aResult)
+  {
+    nsCString str;
+    if (!ReadParam(aMsg, aIter, &str)) {
+      return false;
+    }
+    aResult->SetContentDescription(str);
+    return true;
   }
 
   static bool Read(const Message* aMsg, void** aIter, paramType* aResult)
@@ -781,7 +792,8 @@ struct ParamTraits<mozilla::layers::FrameMetrics>
             ReadParam(aMsg, aIter, &aResult->mUpdateScrollOffset) &&
             ReadParam(aMsg, aIter, &aResult->mScrollGeneration) &&
             ReadParam(aMsg, aIter, &aResult->mTransformScale) &&
-            ReadParam(aMsg, aIter, &aResult->mBackgroundColor));
+            ReadParam(aMsg, aIter, &aResult->mBackgroundColor) &&
+            ReadContentDescription(aMsg, aIter, aResult));
   }
 };
 

gfx/layers/FrameMetrics.h

@@ -13,6 +13,7 @@
 #include "mozilla/gfx/ScaleFactor.h"    // for ScaleFactor
 #include "mozilla/gfx/Logging.h"        // for Log
 #include "gfxColor.h"
+#include "nsString.h"
 
 namespace IPC {
 template <typename T> struct ParamTraits;
@@ -99,7 +100,9 @@ public:
     , mPresShellId(-1)
     , mViewport(0, 0, 0, 0)
     , mBackgroundColor(0, 0, 0, 0)
-  {}
+  {
+    mContentDescription[0] = '\0';
+  }
 
   // Default copy ctor and operator= are fine
 
@@ -125,7 +128,8 @@ public:
            mScrollOffset == aOther.mScrollOffset &&
            mHasScrollgrab == aOther.mHasScrollgrab &&
            mUpdateScrollOffset == aOther.mUpdateScrollOffset &&
-           mBackgroundColor == aOther.mBackgroundColor;
+           mBackgroundColor == aOther.mBackgroundColor &&
+           !strcmp(mContentDescription, aOther.mContentDescription);
   }
   bool operator!=(const FrameMetrics& aOther) const
   {
@@ -480,6 +484,18 @@ public:
     mBackgroundColor = aBackgroundColor;
   }
 
+  nsCString GetContentDescription() const
+  {
+    return nsCString(mContentDescription);
+  }
+
+  void SetContentDescription(const nsCString& aContentDescription)
+  {
+    strncpy(mContentDescription, aContentDescription.get(),
+            sizeof(mContentDescription));
+    mContentDescription[sizeof(mContentDescription) - 1] = 0;
+  }
+
 private:
   // New fields from now on should be made private and old fields should
   // be refactored to be private.
@@ -551,6 +567,11 @@ private:
 
   // The background color to use when overscrolling.
   gfxRGBA mBackgroundColor;
+
+  // A description of the content element corresponding to this frame.
+  // This is empty unless this is a scrollable ContainerLayer and the
+  // apz.printtree pref is turned on.
+  char mContentDescription[20];
 };
 
 /**

gfx/layers/LayerMetricsWrapper.h

@@ -328,13 +328,6 @@ public:
     return mLayer->GetClipRect();
   }
 
-  const std::string& GetContentDescription() const
-  {
-    MOZ_ASSERT(IsValid());
-
-    return mLayer->GetContentDescription();
-  }
-
   // Expose an opaque pointer to the layer. Mostly used for printf
   // purposes. This is not intended to be a general-purpose accessor
   // for the underlying layer.

gfx/layers/Layers.h

@@ -1171,17 +1171,6 @@ public:
     }
   }
 
-  void SetContentDescription(const std::string& aContentDescription)
-  {
-    if (mContentDescription == aContentDescription) {
-      return;
-    }
-
-    MOZ_LAYERS_LOG_IF_SHADOWABLE(this, ("Layer::Mutated(%p) ContentDescription", this));
-    mContentDescription = aContentDescription;
-    Mutated();
-  }
-
   // These getters can be used anytime.
   float GetOpacity() { return mOpacity; }
   gfx::CompositionOp GetMixBlendMode() const { return mMixBlendMode; }
@@ -1215,7 +1204,6 @@ public:
   FrameMetrics::ViewID GetScrollbarTargetContainerId() { return mScrollbarTargetId; }
   ScrollDirection GetScrollbarDirection() { return mScrollbarDirection; }
   Layer* GetMaskLayer() const { return mMaskLayer; }
-  const std::string& GetContentDescription() const { return mContentDescription; }
 
 
   // Note that all lengths in animation data are either in CSS pixels or app
@@ -1643,10 +1631,6 @@ protected:
   // If this layer is used for OMTA, then this counter is used to ensure we
   // stay in sync with the animation manager
   uint64_t mAnimationGeneration;
-  // A description of the content element corresponding to this frame.
-  // This is empty unless this is a scrollable ContainerLayer and the
-  // apz.printtree pref is turned on.
-  std::string mContentDescription;
 #ifdef MOZ_DUMP_PAINTING
   nsTArray<nsCString> mExtraDumpInfo;
 #endif

gfx/layers/apz/src/APZCTreeManager.cpp

@@ -308,7 +308,7 @@ APZCTreeManager::PrepareAPZCForLayer(const LayerMetricsWrapper& aLayer,
                  << "\tsr=" << aMetrics.mScrollableRect
                  << (aLayer.GetVisibleRegion().IsEmpty() ? "\tscrollinfo" : "")
                  << (apzc->HasScrollgrab() ? "\tscrollgrab" : "")
-                 << "\t" << aLayer.GetContentDescription();
+                 << "\t" << aMetrics.GetContentDescription().get();
 
     // Bind the APZC instance into the tree of APZCs
     if (aNextSibling) {

gfx/layers/ipc/LayerTransactionParent.cpp

@@ -321,7 +321,6 @@ LayerTransactionParent::RecvUpdate(const InfallibleTArray<Edit>& cset,
       layer->SetAnimations(common.animations());
       layer->SetInvalidRegion(common.invalidRegion());
       layer->SetFrameMetrics(common.metrics());
-      layer->SetContentDescription(common.contentDescription());
 
       typedef SpecificLayerAttributes Specific;
       const SpecificLayerAttributes& specific = attrs.specific();

gfx/layers/ipc/ShadowLayers.cpp

@@ -609,7 +609,6 @@ ShadowLayerForwarder::EndTransaction(InfallibleTArray<EditReply>* aReplies,
     common.animations() = mutant->GetAnimations();
     common.invalidRegion() = mutant->GetInvalidRegion();
     common.metrics() = mutant->GetAllFrameMetrics();
-    common.contentDescription() = mutant->GetContentDescription();
     attrs.specific() = null_t();
     mutant->FillSpecificAttributes(attrs.specific());
 

layout/base/nsDisplayList.cpp

@@ -835,7 +835,7 @@ static void RecordFrameMetrics(nsIFrame* aForFrame,
     if (nsIContent* content = frameForCompositionBoundsCalculation->GetContent()) {
       nsAutoString contentDescription;
       content->Describe(contentDescription);
-      aRoot->SetContentDescription(NS_LossyConvertUTF16toASCII(contentDescription).get());
+      metrics.SetContentDescription(NS_LossyConvertUTF16toASCII(contentDescription));
     }
   }