Bug 619488 - Inform child processes of the compositor's layer-manager type. r=jones.chris.g a=b-f

gfx/layers/Layers.h

@@ -232,10 +232,12 @@ class THEBES_API LayerManager {
 
 public:
   enum LayersBackend {
-    LAYERS_BASIC = 0,
+    LAYERS_NONE = 0,
+    LAYERS_BASIC,
     LAYERS_OPENGL,
     LAYERS_D3D9,
-    LAYERS_D3D10
+    LAYERS_D3D10,
+    LAYERS_LAST
   };
 
   LayerManager() : mDestroyed(PR_FALSE), mSnapEffectiveTransforms(PR_TRUE)

gfx/layers/ipc/PLayers.ipdl

@@ -54,6 +54,7 @@ using mozilla::GraphicsFilterType;
 using mozilla::layers::FrameMetrics;
 using mozilla::layers::SurfaceDescriptorX11;
 using mozilla::null_t;
+using mozilla::LayersBackend;
 
 /**
  * The layers protocol is spoken between thread contexts that manage
@@ -243,6 +244,9 @@ parent:
   sync Update(Edit[] cset)
     returns (EditReply[] reply);
 
+  sync GetParentType()
+    returns (LayersBackend backend);
+
   async __delete__();
 };
 

gfx/layers/ipc/ShadowLayers.cpp

@@ -123,7 +123,9 @@ struct AutoTxnEnd {
   Transaction* mTxn;
 };
 
-ShadowLayerForwarder::ShadowLayerForwarder() : mShadowManager(NULL)
+ShadowLayerForwarder::ShadowLayerForwarder()
+ : mShadowManager(NULL)
+ , mParentBackend(LayerManager::LAYERS_NONE)
 {
   mTxn = new Transaction();
 }
@@ -372,6 +374,18 @@ ShadowLayerForwarder::EndTransaction(InfallibleTArray<EditReply>* aReplies)
   return PR_TRUE;
 }
 
+LayersBackend
+ShadowLayerForwarder::GetParentBackendType()
+{
+  if (mParentBackend == LayerManager::LAYERS_NONE) {
+    LayersBackend backend;
+    if (mShadowManager->SendGetParentType(&backend)) {
+      mParentBackend = backend;
+    }
+  }
+  return mParentBackend;
+}
+
 static gfxASurface::gfxImageFormat
 OptimalFormatFor(gfxASurface::gfxContentType aContent)
 {

gfx/layers/ipc/ShadowLayers.h

@@ -111,6 +111,8 @@ class Transaction;
 class ShadowLayerForwarder
 {
 public:
+  typedef LayerManager::LayersBackend LayersBackend;
+
   virtual ~ShadowLayerForwarder();
 
   /**
@@ -305,6 +307,8 @@ public:
    */
   PLayerChild* ConstructShadowFor(ShadowableLayer* aLayer);
 
+  LayersBackend GetParentBackendType();
+
 protected:
   ShadowLayerForwarder();
 
@@ -324,6 +328,7 @@ private:
   static void PlatformSyncBeforeUpdate();
 
   Transaction* mTxn;
+  LayersBackend mParentBackend;
 };
 
 

gfx/layers/ipc/ShadowLayersParent.cpp

@@ -444,6 +444,13 @@ ShadowLayersParent::RecvUpdate(const InfallibleTArray<Edit>& cset,
   return true;
 }
 
+bool
+ShadowLayersParent::RecvGetParentType(LayersBackend* aBackend)
+{
+  *aBackend = layer_manager()->GetBackendType();
+  return true;
+}
+
 PLayerParent*
 ShadowLayersParent::AllocPLayer()
 {

gfx/layers/ipc/ShadowLayersParent.h

@@ -72,6 +72,8 @@ protected:
   NS_OVERRIDE virtual bool RecvUpdate(const EditArray& cset,
                                       EditReplyArray* reply);
 
+  NS_OVERRIDE virtual bool RecvGetParentType(LayersBackend* aBackend);
+
   NS_OVERRIDE virtual PLayerParent* AllocPLayer();
   NS_OVERRIDE virtual bool DeallocPLayer(PLayerParent* actor);
 

ipc/glue/IPCMessageUtils.h

@@ -51,6 +51,7 @@
 #include "nsRect.h"
 #include "nsRegion.h"
 #include "gfxASurface.h"
+#include "Layers.h"
 
 #ifdef _MSC_VER
 #pragma warning( disable : 4800 )
@@ -65,10 +66,13 @@
 namespace base { class FileDescriptor { }; }
 #endif
 
+using mozilla::layers::LayerManager;
+
 namespace mozilla {
 
 typedef gfxPattern::GraphicsFilter GraphicsFilterType;
 typedef gfxASurface::gfxSurfaceType gfxSurfaceType;
+typedef LayerManager::LayersBackend LayersBackend;
 
 // XXX there are out of place and might be generally useful.  Could
 // move to nscore.h or something.
@@ -498,6 +502,35 @@ struct ParamTraits<mozilla::gfxSurfaceType>
   }
 };
 
+ template<>
+struct ParamTraits<mozilla::LayersBackend>
+{
+  typedef mozilla::LayersBackend paramType;
+
+  static void Write(Message* msg, const paramType& param)
+  {
+    if (LayerManager::LAYERS_NONE < param &&
+        param < LayerManager::LAYERS_LAST) {
+      WriteParam(msg, int32(param));
+      return;
+    }
+    NS_RUNTIMEABORT("surface type not reached");
+  }
+
+  static bool Read(const Message* msg, void** iter, paramType* result)
+  {
+    int32 type;
+    if (!ReadParam(msg, iter, &type))
+      return false;
+
+    if (LayerManager::LAYERS_NONE < type &&
+        type < LayerManager::LAYERS_LAST) {
+      *result = paramType(type);
+      return true;
+    }
+    return false;
+  }
+};
 
 template<>
 struct ParamTraits<gfxRGBA>