Bug 868259 - Fix BasicCompositor rendering. r=roc

gfx/layers/client/ClientLayerManager.h

@@ -73,7 +73,9 @@ public:
 
   void SetTransactionIncomplete() { mTransactionIncomplete = true; }
 
-  bool HasShadowTarget() { return !!mShadowTarget; } 
+  bool HasShadowTarget() { return !!mShadowTarget; }
+
+  void SetShadowTarget(gfxContext *aTarget) { mShadowTarget = aTarget; }
 
   bool CompositorMightResample() { return mCompositorMightResample; } 
   

widget/cocoa/nsChildView.mm

@@ -51,6 +51,7 @@
 #include "nsRegion.h"
 #include "Layers.h"
 #include "LayerManagerOGL.h"
+#include "ClientLayerManager.h"
 #include "mozilla/layers/LayerManagerComposite.h"
 #include "GLTextureImage.h"
 #include "mozilla/layers/GLManager.h"
@@ -1873,6 +1874,9 @@ void
 nsChildView::PreRender(LayerManager* aManager)
 {
   nsAutoPtr<GLManager> manager(GLManager::CreateGLManager(aManager));
+  if (!manager) {
+    return;
+  }
   NSOpenGLContext *glContext = (NSOpenGLContext *)manager->gl()->GetNativeData(GLContext::NativeGLContext);
   [(ChildView*)mView preRender:glContext];
 }
@@ -2864,6 +2868,10 @@ NSEvent* gLastDragMouseDownEvent = nil;
     painted = mGeckoChild->PaintWindow(region, aIsAlternate);
   } else if (mGeckoChild->GetLayerManager()->GetBackendType() == LAYERS_CLIENT) {
     // We only need this so that we actually get DidPaintWindow fired
+    if (Compositor::GetBackend() == LAYERS_BASIC) {
+      ClientLayerManager *manager = static_cast<ClientLayerManager*>(mGeckoChild->GetLayerManager());
+      manager->SetShadowTarget(targetContext);
+    }
     painted = mGeckoChild->PaintWindow(region, aIsAlternate);
   }
 

widget/gtk2/nsWindow.cpp

@@ -2122,7 +2122,8 @@ nsWindow::OnExposeEvent(cairo_t *cr)
         return TRUE;
     }
     // If this widget uses OMTC...
-    if (GetLayerManager()->AsShadowForwarder() && GetLayerManager()->AsShadowForwarder()->HasShadowManager()) {
+    if (GetLayerManager()->AsShadowForwarder() && GetLayerManager()->AsShadowForwarder()->HasShadowManager() &&
+        Compositor::GetBackend() != LAYERS_BASIC) {
         listener->DidPaintWindow();
 
         g_free(rects);
@@ -2194,8 +2195,14 @@ nsWindow::OnExposeEvent(cairo_t *cr)
 
     bool painted = false;
     {
-      AutoLayerManagerSetup setupLayerManager(this, ctx, layerBuffering);
-      painted = listener->PaintWindow(this, region, 0);
+      if (GetLayerManager()->GetBackendType() == LAYERS_BASIC) {
+        AutoLayerManagerSetup setupLayerManager(this, ctx, layerBuffering);
+        painted = listener->PaintWindow(this, region, 0);
+      } else if (GetLayerManager()->GetBackendType() == LAYERS_CLIENT) {
+        ClientLayerManager *manager = static_cast<ClientLayerManager*>(GetLayerManager());
+        manager->SetShadowTarget(ctx);
+        painted = listener->PaintWindow(this, region, 0);
+      }
     }
 
 #ifdef MOZ_X11

widget/xpwidgets/nsBaseWidget.cpp

@@ -875,6 +875,20 @@ void nsBaseWidget::CreateCompositor()
   CreateCompositor(rect.width, rect.height);
 }
 
+mozilla::layers::LayersBackend
+nsBaseWidget::GetPreferredCompositorBackend()
+{
+  // We need a separate preference here (instead of using mUseLayersAcceleration)
+  // because we force enable accelerated layers with e10s. Once the BasicCompositor
+  // is stable enough to be used for Ripc/Cipc, then we can remove that and this
+  // pref.
+  if (Preferences::GetBool("layers.offmainthreadcomposition.prefer-basic", false)) {
+    return mozilla::layers::LAYERS_BASIC;
+  }
+
+  return mozilla::layers::LAYERS_OPENGL;
+}
+
 void nsBaseWidget::CreateCompositor(int aWidth, int aHeight)
 {
   // Recreating this is tricky, as we may still have an old and we need

widget/xpwidgets/nsBaseWidget.h

@@ -337,8 +337,7 @@ protected:
 
   virtual CompositorChild* GetRemoteRenderer() MOZ_OVERRIDE;
 
-  virtual mozilla::layers::LayersBackend GetPreferredCompositorBackend()
-  { return mUseLayersAcceleration ? mozilla::layers::LAYERS_OPENGL : mozilla::layers::LAYERS_BASIC; }
+  virtual mozilla::layers::LayersBackend GetPreferredCompositorBackend();
 
 protected:
   /**