Bug 1326421 - Add a compositor option for WebRender being enabled or not. r=dvander

MozReview-Commit-ID: LeQRgKSn0Ql

gfx/ipc/CompositorOptions.h

@@ -31,20 +31,25 @@ public:
   // This constructor needed for IPDL purposes, don't use it anywhere else.
   CompositorOptions()
     : mUseAPZ(false)
+    , mUseWebRender(false)
   {
   }
 
-  explicit CompositorOptions(bool aUseAPZ)
+  explicit CompositorOptions(bool aUseAPZ,
+                             bool aUseWebRender)
     : mUseAPZ(aUseAPZ)
+    , mUseWebRender(aUseWebRender)
   {
   }
 
   bool UseAPZ() const { return mUseAPZ; }
+  bool UseWebRender() const { return mUseWebRender; }
 
   friend struct IPC::ParamTraits<CompositorOptions>;
 
 private:
   bool mUseAPZ;
+  bool mUseWebRender;
 
   // Make sure to add new fields to the ParamTraits implementation
 };

gfx/ipc/GfxMessageUtils.h

@@ -1326,10 +1326,12 @@ struct ParamTraits<mozilla::layers::CompositorOptions>
 
   static void Write(Message* aMsg, const paramType& aParam) {
     WriteParam(aMsg, aParam.mUseAPZ);
+    WriteParam(aMsg, aParam.mUseWebRender);
   }
 
   static bool Read(const Message* aMsg, PickleIterator* aIter, paramType* aResult) {
-    return ReadParam(aMsg, aIter, &aResult->mUseAPZ);
+    return ReadParam(aMsg, aIter, &aResult->mUseAPZ)
+        && ReadParam(aMsg, aIter, &aResult->mUseWebRender);
   }
 };
 

widget/nsBaseWidget.cpp

@@ -1298,15 +1298,15 @@ void nsBaseWidget::CreateCompositor(int aWidth, int aHeight)
 
   CreateCompositorVsyncDispatcher();
 
+  CompositorOptions options(UseAPZ(), gfxPrefs::WebRenderEnabled());
+
   RefPtr<LayerManager> lm;
-  if (gfxPrefs::WebRenderEnabled()) {
+  if (options.UseWebRender()) {
     lm = new WebRenderLayerManager(this);
   } else {
     lm = new ClientLayerManager(this);
   }
 
-  CompositorOptions options(UseAPZ());
-
   gfx::GPUProcessManager* gpu = gfx::GPUProcessManager::Get();
   mCompositorSession = gpu->CreateTopLevelCompositor(
     this,

widget/windows/nsWindow.cpp

@@ -3910,7 +3910,7 @@ nsWindow::GetLayerManager(PLayerTransactionChild* aShadowManager,
       reinterpret_cast<uintptr_t>(static_cast<nsIWidget*>(this)),
       mTransparencyMode);
     // If we're not using the compositor, the options don't actually matter.
-    CompositorOptions options(false);
+    CompositorOptions options(false, false);
     mBasicLayersSurface = new InProcessWinCompositorWidget(initData, options, this);
     mCompositorWidgetDelegate = mBasicLayersSurface;
     mLayerManager = CreateBasicLayerManager();