Revert "Revert "Make threaded proxy generation MDB-friendly, and defer instantiation""

This reverts commit 837c6c7c0cc76bdb9d61a05244ca5f31e7573c37.

Bug: skia:
Change-Id: I1821f1b2b772c67f1b749692b398eb757d8073c9
Reviewed-on: https://skia-review.googlesource.com/52744
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>

12 files changed, 190 insertions, 131 deletions

diff --git a/gn/gpu.gni b/gn/gpu.gni
index 362dac86a2..b026e824fb 100644
--- a/gn/gpu.gni
+++ b/gn/gpu.gni
@@ -72,6 +72,7 @@ skia_gpu_sources = [
   "$_src/gpu/GrCoordTransform.h",
   "$_src/gpu/GrDefaultGeoProcFactory.cpp",
   "$_src/gpu/GrDefaultGeoProcFactory.h",
+  "$_src/gpu/GrDeferredProxyUploader.h",
   "$_src/gpu/GrDistanceFieldGenFromVector.cpp",
   "$_src/gpu/GrDistanceFieldGenFromVector.h",
   "$_src/gpu/GrDrawingManager.cpp",
@@ -127,7 +128,6 @@ skia_gpu_sources = [
   "$_src/gpu/GrOnFlushResourceProvider.h",
   "$_src/gpu/GrPipeline.cpp",
   "$_src/gpu/GrPipeline.h",
-  "$_src/gpu/GrPrepareCallback.h",
   "$_src/gpu/GrPrimitiveProcessor.cpp",
   "$_src/gpu/GrPrimitiveProcessor.h",
   "$_src/gpu/GrProcessorSet.cpp",
diff --git a/include/private/GrTextureProxy.h b/include/private/GrTextureProxy.h
index 8e72eaddb9..e841baeb1f 100644
--- a/include/private/GrTextureProxy.h
+++ b/include/private/GrTextureProxy.h
@@ -12,6 +12,7 @@
 #include "GrSurfaceProxy.h"
 
 class GrCaps;
+class GrDeferredProxyUploader;
 class GrResourceCache;
 class GrResourceProvider;
 class GrTextureOpList;
@@ -69,6 +70,7 @@ public:
 
 protected:
     friend class GrSurfaceProxy; // for ctors
+    friend class GrTextureProxyPriv;
 
     // Deferred version
     GrTextureProxy(const GrSurfaceDesc& srcDesc, SkBackingFit, SkBudgeted,
@@ -89,6 +91,11 @@ private:
     GrUniqueKey fUniqueKey;
     GrResourceCache* fCache; // only set when fUniqueKey is valid
 
+    // Only used for proxies whose contents are being prepared on a worker thread. This object
+    // stores the texture data, allowing the proxy to remain uninstantiated until flush. At that
+    // point, the proxy is instantiated, and this data is used to perform an ASAP upload.
+    std::unique_ptr<GrDeferredProxyUploader> fDeferredUploader;
+
     size_t onUninstantiatedGpuMemorySize() const override;
 
     // Methods made available via GrTextureProxy::CacheAccess
diff --git a/src/gpu/GrClipStackClip.cpp b/src/gpu/GrClipStackClip.cpp
index 10880b4891..309c9cad10 100644
--- a/src/gpu/GrClipStackClip.cpp
+++ b/src/gpu/GrClipStackClip.cpp
@@ -9,11 +9,11 @@
 
 #include "GrAppliedClip.h"
 #include "GrContextPriv.h"
+#include "GrDeferredProxyUploader.h"
 #include "GrDrawingManager.h"
 #include "GrRenderTargetContextPriv.h"
 #include "GrFixedClip.h"
 #include "GrGpuResourcePriv.h"
-#include "GrPrepareCallback.h"
 #include "GrResourceProvider.h"
 #include "GrStencilAttachment.h"
 #include "GrSWMaskHelper.h"
@@ -428,7 +428,7 @@ sk_sp<GrTextureProxy> GrClipStackClip::createAlphaClipMask(GrContext* context,
 namespace {
 
 /**
- * Payload class for use with GrMaskUploaderPrepareCallback. The clip mask code renders multiple
+ * Payload class for use with GrTDeferredProxyUploader. The clip mask code renders multiple
  * elements, each storing their own AA setting (and already transformed into device space). This
  * stores all of the information needed by the worker thread to draw all clip elements (see below,
  * in createSoftwareClipMask).
@@ -526,15 +526,8 @@ sk_sp<GrTextureProxy> GrClipStackClip::createSoftwareClipMask(
         proxy = GrSurfaceProxy::MakeDeferred(context->resourceProvider(), desc,
                                              SkBackingFit::kApprox, SkBudgeted::kYes);
 
-        // TODO: I believe the assignUniqueKeyToProxy below used to instantiate the proxy before
-        // the draw that used the result was being flushed, so the upload was succeeding. With 
-        // assignUniqueKeyToProxy no longer forcing an instantiation it will have to happen
-        // explicitly elsewhere.
-        proxy->instantiate(context->resourceProvider());
-
-        auto uploader = skstd::make_unique<GrMaskUploaderPrepareCallback<ClipMaskData>>(
-                proxy, reducedClip);
-        GrMaskUploaderPrepareCallback<ClipMaskData>* uploaderRaw = uploader.get();
+        auto uploader = skstd::make_unique<GrTDeferredProxyUploader<ClipMaskData>>(reducedClip);
+        GrTDeferredProxyUploader<ClipMaskData>* uploaderRaw = uploader.get();
         auto drawAndUploadMask = [uploaderRaw, maskSpaceIBounds] {
             TRACE_EVENT0("skia", "Threaded SW Clip Mask Render");
             GrSWMaskHelper helper(uploaderRaw->getPixels());
@@ -545,11 +538,11 @@ sk_sp<GrTextureProxy> GrClipStackClip::createSoftwareClipMask(
             } else {
                 SkDEBUGFAIL("Unable to allocate SW clip mask.");
             }
-            uploaderRaw->getSemaphore()->signal();
+            uploaderRaw->signalAndFreeData();
         };
 
         taskGroup->add(std::move(drawAndUploadMask));
-        renderTargetContext->getOpList()->addPrepareCallback(std::move(uploader));
+        proxy->texPriv().setDeferredUploader(std::move(uploader));
     } else {
         GrSWMaskHelper helper;
         if (!helper.init(maskSpaceIBounds)) {
diff --git a/src/gpu/GrDeferredProxyUploader.h b/src/gpu/GrDeferredProxyUploader.h
new file mode 100644
index 0000000000..35581166de
--- /dev/null
+++ b/src/gpu/GrDeferredProxyUploader.h
@@ -0,0 +1,108 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrDeferredProxyUploader_DEFINED
+#define GrDeferredProxyUploader_DEFINED
+
+#include "SkAutoPixmapStorage.h"
+#include "SkMakeUnique.h"
+#include "SkRefCnt.h"
+#include "SkSemaphore.h"
+
+#include "GrOpFlushState.h"
+#include "GrTextureProxyPriv.h"
+
+/**
+ * GrDeferredProxyUploader assists with threaded generation of textures. Currently used by both
+ * software clip masks, and the software path renderer. The calling code typically needs to store
+ * some additional data (T) for use on the worker thread. GrTDeferredProxyUploader allows storing
+ * such data. The common flow is:
+ *
+ * 1) A GrTDeferredProxyUploader is created, with some payload (eg an SkPath to draw).
+ *    The uploader is owned by the proxy that it's going to populate.
+ * 2) A task is created with a pointer to the uploader. A worker thread executes that task, using
+ *    the payload data to allocate and fill in the fPixels pixmap.
+ * 3) The worker thread calls signalAndFreeData(), which notifies the main thread that the pixmap
+ *    is ready, and then deletes the payload data (which is no longer needed).
+ * 4) In parallel to 2-3, on the main thread... Some op is created that refers to the proxy. When
+ *    that op is added to an op list, the op list retains a pointer to the "deferred" proxies.
+ * 5) At flush time, the op list ensures that the deferred proxies are instantiated, then calls
+ *    scheduleUpload on those proxies, which calls scheduleUpload on the uploader (below).
+ * 6) scheduleUpload defers the upload even further, by adding an ASAPUpload to the flush.
+ * 7) When the ASAP upload happens, we wait to make sure that the pixels are marked ready
+ *    (from step #3 on the worker thread). Then we perform the actual upload to the texture.
+ *    Finally, we call resetDeferredUploader, which deletes the uploader object, causing fPixels
+ *    to be freed.
+ */
+class GrDeferredProxyUploader : public SkNoncopyable {
+public:
+    GrDeferredProxyUploader() : fScheduledUpload(false), fWaited(false) {}
+
+    virtual ~GrDeferredProxyUploader() {
+        if (!fWaited) {
+            // This can happen if our owning proxy fails to instantiate
+            fPixelsReady.wait();
+        }
+    }
+
+    void scheduleUpload(GrOpFlushState* flushState, GrTextureProxy* proxy) {
+        if (fScheduledUpload) {
+            // Multiple references to the owning proxy may have caused us to already execute
+            return;
+        }
+
+        auto uploadMask = [this, proxy](GrDrawOp::WritePixelsFn& writePixelsFn) {
+            this->fPixelsReady.wait();
+            this->fWaited = true;
+            // If the worker thread was unable to allocate pixels, this check will fail, and we'll
+            // end up drawing with an uninitialized mask texture, but at least we won't crash.
+            if (this->fPixels.addr()) {
+                writePixelsFn(proxy, 0, 0, this->fPixels.width(), this->fPixels.height(),
+                              proxy->config(), this->fPixels.addr(), this->fPixels.rowBytes());
+            }
+            // Upload has finished, so tell the proxy to release this GrDeferredProxyUploader
+            proxy->texPriv().resetDeferredUploader();
+        };
+        flushState->addASAPUpload(std::move(uploadMask));
+        fScheduledUpload = true;
+    }
+
+    void signalAndFreeData() {
+        fPixelsReady.signal();
+        this->freeData();
+    }
+
+    SkAutoPixmapStorage* getPixels() { return &fPixels; }
+
+private:
+    virtual void freeData() {}
+
+    SkAutoPixmapStorage fPixels;
+    SkSemaphore fPixelsReady;
+    bool fScheduledUpload;
+    bool fWaited;
+};
+
+template <typename T>
+class GrTDeferredProxyUploader : public GrDeferredProxyUploader {
+public:
+    template <typename... Args>
+    GrTDeferredProxyUploader(Args&&... args)
+        : fData(skstd::make_unique<T>(std::forward<Args>(args)...)) {
+    }
+
+    T& data() { return *fData; }
+
+private:
+    void freeData() override {
+        fData.reset();
+    }
+
+    std::unique_ptr<T> fData;
+};
+
+#endif
diff --git a/src/gpu/GrDrawingManager.cpp b/src/gpu/GrDrawingManager.cpp
index 013c624efa..5deacbb5ca 100644
--- a/src/gpu/GrDrawingManager.cpp
+++ b/src/gpu/GrDrawingManager.cpp
@@ -195,6 +195,8 @@ GrSemaphoresSubmitted GrDrawingManager::internalFlush(GrSurfaceProxy*,
             continue;
         }
 
+        // Instantiate all deferred proxies (being built on worker threads) so we can upload them
+        fOpLists[i]->instantiateDeferredProxies(fContext->resourceProvider());
         fOpLists[i]->prepare(&fFlushState);
     }
 
diff --git a/src/gpu/GrOpList.cpp b/src/gpu/GrOpList.cpp
index 65d4e73fd0..59e1cd0f23 100644
--- a/src/gpu/GrOpList.cpp
+++ b/src/gpu/GrOpList.cpp
@@ -8,8 +8,9 @@
 #include "GrOpList.h"
 
 #include "GrContext.h"
-#include "GrPrepareCallback.h"
+#include "GrDeferredProxyUploader.h"
 #include "GrSurfaceProxy.h"
+#include "GrTextureProxyPriv.h"
 
 #include "SkAtomics.h"
 
@@ -57,17 +58,19 @@ void GrOpList::reset() {
     }
 
     fTarget.reset();
-    fPrepareCallbacks.reset();
+    fDeferredProxies.reset();
     fAuditTrail = nullptr;
 }
 
-void GrOpList::addPrepareCallback(std::unique_ptr<GrPrepareCallback> callback) {
-    fPrepareCallbacks.push_back(std::move(callback));
+void GrOpList::instantiateDeferredProxies(GrResourceProvider* resourceProvider) {
+    for (int i = 0; i < fDeferredProxies.count(); ++i) {
+        fDeferredProxies[i]->instantiate(resourceProvider);
+    }
 }
 
 void GrOpList::prepare(GrOpFlushState* flushState) {
-    for (int i = 0; i < fPrepareCallbacks.count(); ++i) {
-        (*fPrepareCallbacks[i])(flushState);
+    for (int i = 0; i < fDeferredProxies.count(); ++i) {
+        fDeferredProxies[i]->texPriv().scheduleUpload(flushState);
     }
 
     this->onPrepare(flushState);
@@ -100,6 +103,12 @@ void GrOpList::addDependency(GrSurfaceProxy* dependedOn, const GrCaps& caps) {
             opList->makeClosed(caps);
         }
     }
+
+    if (GrTextureProxy* textureProxy = dependedOn->asTextureProxy()) {
+        if (textureProxy->texPriv().isDeferred()) {
+            fDeferredProxies.push_back(textureProxy);
+        }
+    }
 }
 
 #ifdef SK_DEBUG
diff --git a/src/gpu/GrOpList.h b/src/gpu/GrOpList.h
index 7a97961b19..1f98ddc41b 100644
--- a/src/gpu/GrOpList.h
+++ b/src/gpu/GrOpList.h
@@ -23,7 +23,6 @@
 class GrAuditTrail;
 class GrCaps;
 class GrOpFlushState;
-class GrPrepareCallback;
 class GrRenderTargetOpList;
 class GrResourceAllocator;
 class GrResourceProvider;
@@ -39,8 +38,10 @@ public:
     GrOpList(GrResourceProvider*, GrSurfaceProxy*, GrAuditTrail*);
     ~GrOpList() override;
 
-    // These three methods are invoked at flush time
+    // These four methods are invoked at flush time
     bool instantiate(GrResourceProvider* resourceProvider);
+    // Instantiates any "threaded" texture proxies that are being prepared elsewhere
+    void instantiateDeferredProxies(GrResourceProvider* resourceProvider);
     void prepare(GrOpFlushState* flushState);
     bool execute(GrOpFlushState* flushState) { return this->onExecute(flushState); }
 
@@ -59,8 +60,6 @@ public:
 
     virtual void reset();
 
-    void addPrepareCallback(std::unique_ptr<GrPrepareCallback> callback);
-
     // TODO: in an MDB world, where the OpLists don't allocate GPU resources, it seems like
     // these could go away
     virtual void abandonGpuResources() = 0;
@@ -119,6 +118,9 @@ protected:
     GrColor           fLoadClearColor = 0x0;
     GrLoadOp          fStencilLoadOp  = GrLoadOp::kLoad;
 
+    // List of texture proxies whose contents are being prepared on a worker thread
+    SkTArray<GrTextureProxy*, true> fDeferredProxies;
+
 private:
     friend class GrDrawingManager; // for resetFlag, TopoSortTraits & gatherProxyIntervals
 
@@ -181,9 +183,6 @@ private:
     // 'this' GrOpList relies on the output of the GrOpLists in 'fDependencies'
     SkSTArray<1, GrOpList*, true> fDependencies;
 
-    // These are used rarely, most clients never produce any
-    SkTArray<std::unique_ptr<GrPrepareCallback>> fPrepareCallbacks;
-
     typedef SkRefCnt INHERITED;
 };
 
diff --git a/src/gpu/GrPrepareCallback.h b/src/gpu/GrPrepareCallback.h
deleted file mode 100644
index af8161d163..0000000000
--- a/src/gpu/GrPrepareCallback.h
+++ /dev/null
@@ -1,88 +0,0 @@
-/*
- * Copyright 2017 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef GrPrepareCallback_DEFINED
-#define GrPrepareCallback_DEFINED
-
-#include "SkAutoPixmapStorage.h"
-#include "SkRefCnt.h"
-#include "SkSemaphore.h"
-
-#include "GrOpFlushState.h"
-
-class GrTextureProxy;
-
-/**
- * An instance of any class derived from GrPrepareCallback can be passed to
- * GrOpList::addPrepareCallback. At flush time, all callbacks (on op lists being flushed) will be
- * invoked (via operator()). Note that the callback receives the GrOpFlushState, so it can trigger
- * ASAP uploads (similar to an Op's onPrepare).
- *
- * All callbacks are invoked at the beginning of flush, before prepare is called.
- */
-class GrPrepareCallback : SkNoncopyable {
-public:
-    virtual ~GrPrepareCallback() {}
-    virtual void operator()(GrOpFlushState*) = 0;
-};
-
-/**
- * GrMaskUploaderPrepareCallback assists with threaded generation of mask textures. Currently used
- * by both software clip masks, and the software path renderer. The calling code typically needs
- * to store some additional data (T) for use on the worker thread. That payload is accessed by the
- * worker thread to populate the mask in fPixels (using GrSWMaskHelper). This callback's operator()
- * handles scheduling the texture upload at flush time.
- */
-template <typename T>
-class GrMaskUploaderPrepareCallback : public GrPrepareCallback {
-public:
-    template <typename... Args>
-    GrMaskUploaderPrepareCallback(sk_sp<GrTextureProxy> proxy, Args&&... args)
-            : fProxy(std::move(proxy))
-            , fWaited(false)
-            , fData(std::forward<Args>(args)...) {}
-
-    ~GrMaskUploaderPrepareCallback() override {
-        if (!fWaited) {
-            // This can happen if our owning op list fails to instantiate (so it never prepares)
-            fPixelsReady.wait();
-        }
-    }
-
-    void operator()(GrOpFlushState* flushState) override {
-        auto uploadMask = [this](GrDrawOp::WritePixelsFn& writePixelsFn) {
-            this->fPixelsReady.wait();
-            this->fWaited = true;
-            // If the worker thread was unable to allocate pixels, this check will fail, and we'll
-            // end up drawing with an uninitialized mask texture, but at least we won't crash.
-            if (this->fPixels.addr()) {
-                writePixelsFn(this->fProxy.get(), 0, 0,
-                              this->fPixels.width(), this->fPixels.height(),
-                              kAlpha_8_GrPixelConfig,
-                              this->fPixels.addr(), this->fPixels.rowBytes());
-                // Free this memory immediately, so it can be recycled. This avoids memory pressure
-                // when there is a large amount of threaded work still running during flush.
-                this->fPixels.reset();
-            }
-        };
-        flushState->addASAPUpload(std::move(uploadMask));
-    }
-
-    SkAutoPixmapStorage* getPixels() { return &fPixels; }
-    SkSemaphore* getSemaphore() { return &fPixelsReady; }
-    T& data() { return fData; }
-
-private:
-    sk_sp<GrTextureProxy> fProxy;
-    SkAutoPixmapStorage fPixels;
-    SkSemaphore fPixelsReady;
-    bool fWaited;
-
-    T fData;
-};
-
-#endif
diff --git a/src/gpu/GrRenderTargetOpList.cpp b/src/gpu/GrRenderTargetOpList.cpp
index 15cb4f16c6..bc293bb1e3 100644
--- a/src/gpu/GrRenderTargetOpList.cpp
+++ b/src/gpu/GrRenderTargetOpList.cpp
@@ -221,6 +221,7 @@ void GrRenderTargetOpList::fullClear(const GrCaps& caps, GrColor color) {
     // buffer we will need a more elaborate tracking system (skbug.com/7002).
     if (this->isEmpty() || !fTarget.get()->asRenderTargetProxy()->needsStencil()) {
         fRecordedOps.reset();
+        fDeferredProxies.reset();
         fColorLoadOp = GrLoadOp::kClear;
         fLoadClearColor = color;
         return;
diff --git a/src/gpu/GrSoftwarePathRenderer.cpp b/src/gpu/GrSoftwarePathRenderer.cpp
index dd0e272dbb..8c3d64b77a 100644
--- a/src/gpu/GrSoftwarePathRenderer.cpp
+++ b/src/gpu/GrSoftwarePathRenderer.cpp
@@ -9,10 +9,10 @@
 #include "GrAuditTrail.h"
 #include "GrClip.h"
 #include "GrContextPriv.h"
+#include "GrDeferredProxyUploader.h"
 #include "GrGpuResourcePriv.h"
 #include "GrOpFlushState.h"
 #include "GrOpList.h"
-#include "GrPrepareCallback.h"
 #include "GrResourceProvider.h"
 #include "GrSWMaskHelper.h"
 #include "SkMakeUnique.h"
@@ -175,7 +175,7 @@ static sk_sp<GrTextureProxy> make_deferred_mask_texture_proxy(GrContext* context
 namespace {
 
 /**
- * Payload class for use with GrMaskUploaderPrepareCallback. The software path renderer only draws
+ * Payload class for use with GrTDeferredProxyUploader. The software path renderer only draws
  * a single path into the mask texture. This stores all of the information needed by the worker
  * thread's call to drawShape (see below, in onDrawPath).
  */
@@ -318,15 +318,9 @@ bool GrSoftwarePathRenderer::onDrawPath(const DrawPathArgs& args) {
                 return false;
             }
 
-            // TODO: I believe the assignUniqueKeyToProxy below used to instantiate the proxy before
-            // before the draw that used the result was being flushed, so the upload was succeeding.
-            // With assignUniqueKeyToProxy no longer forcing an instantiation it will have to happen
-            // explicitly elsewhere.
-            proxy->instantiate(fResourceProvider);
-
-            auto uploader = skstd::make_unique<GrMaskUploaderPrepareCallback<SoftwarePathData>>(
-                    proxy, *boundsForMask, *args.fViewMatrix, *args.fShape, aa);
-            GrMaskUploaderPrepareCallback<SoftwarePathData>* uploaderRaw = uploader.get();
+            auto uploader = skstd::make_unique<GrTDeferredProxyUploader<SoftwarePathData>>(
+                    *boundsForMask, *args.fViewMatrix, *args.fShape, aa);
+            GrTDeferredProxyUploader<SoftwarePathData>* uploaderRaw = uploader.get();
 
             auto drawAndUploadMask = [uploaderRaw] {
                 TRACE_EVENT0("skia", "Threaded SW Mask Render");
@@ -338,10 +332,10 @@ bool GrSoftwarePathRenderer::onDrawPath(const DrawPathArgs& args) {
                 } else {
                     SkDEBUGFAIL("Unable to allocate SW mask.");
                 }
-                uploaderRaw->getSemaphore()->signal();
+                uploaderRaw->signalAndFreeData();
             };
             taskGroup->add(std::move(drawAndUploadMask));
-            args.fRenderTargetContext->getOpList()->addPrepareCallback(std::move(uploader));
+            proxy->texPriv().setDeferredUploader(std::move(uploader));
         } else {
             GrSWMaskHelper helper;
             if (!helper.init(*boundsForMask)) {
diff --git a/src/gpu/GrTextureProxy.cpp b/src/gpu/GrTextureProxy.cpp
index 8b9e58b594..534adaa709 100644
--- a/src/gpu/GrTextureProxy.cpp
+++ b/src/gpu/GrTextureProxy.cpp
@@ -6,10 +6,11 @@
  */
 
 #include "GrTextureProxy.h"
+#include "GrTextureProxyPriv.h"
 
 #include "GrContext.h"
+#include "GrDeferredProxyUploader.h"
 #include "GrResourceCache.h"
-
 #include "GrTexturePriv.h"
 
 GrTextureProxy::GrTextureProxy(const GrSurfaceDesc& srcDesc, SkBackingFit fit, SkBudgeted budgeted,
@@ -17,7 +18,8 @@ GrTextureProxy::GrTextureProxy(const GrSurfaceDesc& srcDesc, SkBackingFit fit, S
         : INHERITED(srcDesc, fit, budgeted, flags)
         , fIsMipMapped(false)
         , fMipColorMode(SkDestinationSurfaceColorMode::kLegacy)
-        , fCache(nullptr) {
+        , fCache(nullptr)
+        , fDeferredUploader(nullptr) {
     SkASSERT(!srcData);  // currently handled in Make()
 }
 
@@ -25,7 +27,8 @@ GrTextureProxy::GrTextureProxy(sk_sp<GrSurface> surf, GrSurfaceOrigin origin)
         : INHERITED(std::move(surf), origin, SkBackingFit::kExact)
         , fIsMipMapped(fTarget->asTexture()->texturePriv().hasMipMaps())
         , fMipColorMode(fTarget->asTexture()->texturePriv().mipColorMode())
-        , fCache(nullptr) {
+        , fCache(nullptr)
+        , fDeferredUploader(nullptr) {
     if (fTarget->getUniqueKey().isValid()) {
         fCache = fTarget->asTexture()->getContext()->getResourceCache();
         fCache->adoptUniqueKeyFromSurface(this, fTarget);
@@ -67,6 +70,25 @@ sk_sp<GrSurface> GrTextureProxy::createSurface(GrResourceProvider* resourceProvi
     return surface;
 }
 
+void GrTextureProxyPriv::setDeferredUploader(std::unique_ptr<GrDeferredProxyUploader> uploader) {
+    SkASSERT(!fTextureProxy->fDeferredUploader);
+    fTextureProxy->fDeferredUploader = std::move(uploader);
+}
+
+void GrTextureProxyPriv::scheduleUpload(GrOpFlushState* flushState) {
+    SkASSERT(fTextureProxy->fDeferredUploader);
+
+    // Instantiate might have failed
+    if (fTextureProxy->fTarget) {
+        fTextureProxy->fDeferredUploader->scheduleUpload(flushState, fTextureProxy);
+    }
+}
+
+void GrTextureProxyPriv::resetDeferredUploader() {
+    SkASSERT(fTextureProxy->fDeferredUploader);
+    fTextureProxy->fDeferredUploader.reset();
+}
+
 // This method parallels the highest_filter_mode functions in GrGLTexture & GrVkTexture.
 GrSamplerState::Filter GrTextureProxy::highestFilterMode() const {
     if (fTarget) {
diff --git a/src/gpu/GrTextureProxyPriv.h b/src/gpu/GrTextureProxyPriv.h
index c3ddb9460c..e961493179 100644
--- a/src/gpu/GrTextureProxyPriv.h
+++ b/src/gpu/GrTextureProxyPriv.h
@@ -10,11 +10,23 @@
 
 #include "GrTextureProxy.h"
 
+class GrDeferredProxyUploader;
+class GrOpFlushState;
+
 /**
  * This class hides the more specialized capabilities of GrTextureProxy.
  */
 class GrTextureProxyPriv {
 public:
+    // Attach a deferred uploader to the proxy. Holds data being prepared by a worker thread.
+    void setDeferredUploader(std::unique_ptr<GrDeferredProxyUploader>);
+    bool isDeferred() const { return SkToBool(fTextureProxy->fDeferredUploader.get()); }
+    // For a deferred proxy (one that has a deferred uploader attached), this schedules an ASAP
+    // upload of that data to the instantiated texture.
+    void scheduleUpload(GrOpFlushState*);
+    // Clears any deferred uploader object on the proxy. Used to free the CPU data after the
+    // contents have been uploaded.
+    void resetDeferredUploader();
 
 private:
     explicit GrTextureProxyPriv(GrTextureProxy* textureProxy) : fTextureProxy(textureProxy) {}