Bug 1513308 - Lazily initialize DirectX devices for WebRender r=mattwoodrow

gfx/gl/GLScreenBuffer.cpp

@@ -102,6 +102,11 @@ UniquePtr<GLScreenBuffer> GLScreenBuffer::Create(GLContext* gl,
 #endif
   } else if (useD3D) {
 #ifdef XP_WIN
+    // Ensure devices initialization. SharedSurfaceANGLE and
+    // SharedSurfaceD3D11Interop use them. The devices are lazily initialized
+    // with WebRender to reduce memory usage.
+    gfxPlatform::GetPlatform()->EnsureDevicesInitialized();
+
     // Enable surface sharing only if ANGLE and compositing devices
     // are both WARP or both not WARP
     gfx::DeviceManagerDx* dm = gfx::DeviceManagerDx::Get();

gfx/layers/d3d11/TextureD3D11.cpp

@@ -1615,7 +1615,8 @@ bool SyncObjectD3D11Host::Synchronize(bool aFallible) {
 SyncObjectD3D11Client::SyncObjectD3D11Client(SyncHandle aSyncHandle,
                                              ID3D11Device* aDevice)
     : mSyncHandle(aSyncHandle), mSyncLock("SyncObjectD3D11") {
-  if (!aDevice) {
+  if (!aDevice && !XRE_IsGPUProcess() &&
+      gfxPlatform::GetPlatform()->DevicesInitialized()) {
     mDevice = DeviceManagerDx::Get()->GetContentDevice();
     return;
   }
@@ -1664,7 +1665,17 @@ void SyncObjectD3D11Client::RegisterTexture(ID3D11Texture2D* aTexture) {
 }
 
 bool SyncObjectD3D11Client::IsSyncObjectValid() {
-  RefPtr<ID3D11Device> dev = DeviceManagerDx::Get()->GetContentDevice();
+  RefPtr<ID3D11Device> dev;
+  // There is a case that devices are not initialized yet with WebRender.
+  if (gfxPlatform::GetPlatform()->DevicesInitialized()) {
+    dev = DeviceManagerDx::Get()->GetContentDevice();
+  }
+
+  // Update mDevice if the ContentDevice initialization is detected.
+  if (!mDevice && dev && NS_IsMainThread() && gfxVars::UseWebRender()) {
+    mDevice = dev;
+  }
+
   if (!dev || (NS_IsMainThread() && dev != mDevice)) {
     return false;
   }

gfx/layers/wr/WebRenderBridgeChild.cpp

@@ -546,6 +546,11 @@ ipc::IShmemAllocator* WebRenderBridgeChild::GetShmemAllocator() {
 
 RefPtr<KnowsCompositor> WebRenderBridgeChild::GetForMedia() {
   MOZ_ASSERT(NS_IsMainThread());
+
+  // Ensure devices initialization for video playback. The devices are lazily
+  // initialized with WebRender to reduce memory usage.
+  gfxPlatform::GetPlatform()->EnsureDevicesInitialized();
+
   return MakeAndAddRef<KnowsCompositorMediaProxy>(
       GetTextureFactoryIdentifier());
 }

gfx/layers/wr/WebRenderLayerManager.cpp

@@ -665,6 +665,11 @@ void WebRenderLayerManager::SetRoot(Layer* aLayer) {
 already_AddRefed<PersistentBufferProvider>
 WebRenderLayerManager::CreatePersistentBufferProvider(
     const gfx::IntSize& aSize, gfx::SurfaceFormat aFormat) {
+
+  // Ensure devices initialization for canvas 2d. The devices are lazily
+  // initialized with WebRender to reduce memory usage.
+  gfxPlatform::GetPlatform()->EnsureDevicesInitialized();
+
   if (gfxPrefs::PersistentBufferProviderSharedEnabled()) {
     RefPtr<PersistentBufferProvider> provider =
         PersistentBufferProviderShared::Create(aSize, aFormat,

gfx/thebes/DeviceManagerDx.cpp

@@ -991,6 +991,9 @@ RefPtr<ID3D11Device> DeviceManagerDx::GetCompositorDevice() {
 }
 
 RefPtr<ID3D11Device> DeviceManagerDx::GetContentDevice() {
+  MOZ_ASSERT(XRE_IsGPUProcess() ||
+             gfxPlatform::GetPlatform()->DevicesInitialized());
+
   MutexAutoLock lock(mDeviceLock);
   return mContentDevice;
 }

gfx/thebes/gfxPlatform.cpp

@@ -913,6 +913,13 @@ void gfxPlatform::Init() {
 #endif
   gPlatform->InitAcceleration();
   gPlatform->InitWebRenderConfig();
+  // When using WebRender, we defer initialization of the D3D11 devices until
+  // the (rare) cases where they're used. Note that the GPU process where WebRender
+  // runs doesn't initialize gfxPlatform and performs explicit initialization of
+  // the bits it needs.
+  if (!gfxVars::UseWebRender()) {
+    gPlatform->EnsureDevicesInitialized();
+  }
   gPlatform->InitOMTPConfig();
 
   if (gfxConfig::IsEnabled(Feature::GPU_PROCESS)) {

gfx/thebes/gfxPlatform.h

@@ -752,6 +752,9 @@ class gfxPlatform : public mozilla::layers::MemoryPressureListener {
   virtual void OnMemoryPressure(
       mozilla::layers::MemoryPressureReason aWhy) override;
 
+  virtual void EnsureDevicesInitialized() {};
+  virtual bool DevicesInitialized() { return true; };
+
  protected:
   gfxPlatform();
   virtual ~gfxPlatform();

gfx/thebes/gfxWindowsPlatform.cpp

@@ -424,7 +424,6 @@ void gfxWindowsPlatform::InitAcceleration() {
   DeviceManagerDx::Init();
 
   InitializeConfig();
-  InitializeDevices();
   UpdateANGLEConfig();
   UpdateRenderMode();
 
@@ -497,7 +496,9 @@ bool gfxWindowsPlatform::HandleDeviceReset() {
   gfxConfig::Reset(Feature::DIRECT2D);
 
   InitializeConfig();
-  InitializeDevices();
+  if (mInitializedDevices) {
+    InitializeDevices();
+  }
   UpdateANGLEConfig();
   return true;
 }
@@ -1470,7 +1471,25 @@ void gfxWindowsPlatform::InitializeD3D11Config() {
                         uint32_t(aDevice));
 }
 
+// Supports lazy device initialization on Windows, so that WebRender can avoid
+// initializing GPU state and allocating swap chains for most non-GPU processes.
+void gfxWindowsPlatform::EnsureDevicesInitialized() {
+  if (!mInitializedDevices) {
+    mInitializedDevices = true;
+    InitializeDevices();
+    UpdateBackendPrefs();
+  }
+}
+
+bool
+gfxWindowsPlatform::DevicesInitialized() {
+
+  return mInitializedDevices;
+}
+
 void gfxWindowsPlatform::InitializeDevices() {
+  MOZ_ASSERT(NS_IsMainThread());
+
   if (XRE_IsParentProcess()) {
     // If we're the UI process, and the GPU process is enabled, then we don't
     // initialize any DirectX devices. We do leave them enabled in gfxConfig
@@ -2032,6 +2051,10 @@ void gfxWindowsPlatform::BuildContentDeviceData(ContentDeviceData* aOut) {
 }
 
 bool gfxWindowsPlatform::SupportsPluginDirectDXGIDrawing() {
+  // Ensure devices initialization for plugin's DXGISurface. The devices are
+  // lazily initialized with WebRender to reduce memory usage.
+  EnsureDevicesInitialized();
+
   DeviceManagerDx* dm = DeviceManagerDx::Get();
   if (!dm->GetContentDevice() || !dm->TextureSharingWorks()) {
     return false;

gfx/thebes/gfxWindowsPlatform.h

@@ -105,6 +105,9 @@ class gfxWindowsPlatform : public gfxPlatform {
     return (gfxWindowsPlatform*)gfxPlatform::GetPlatform();
   }
 
+  virtual void EnsureDevicesInitialized() override;
+  virtual bool DevicesInitialized() override;
+
   virtual gfxPlatformFontList* CreatePlatformFontList() override;
 
   virtual already_AddRefed<gfxASurface> CreateOffscreenSurface(
@@ -259,6 +262,7 @@ class gfxWindowsPlatform : public gfxPlatform {
   DWRITE_MEASURING_MODE mMeasuringMode;
 
   RefPtr<mozilla::layers::ReadbackManagerD3D11> mD3D11ReadbackManager;
+  bool mInitializedDevices = false;
 };
 
 #endif /* GFX_WINDOWS_PLATFORM_H */