diff -r 000000000000 -r 6474c204b198 gfx/skia/trunk/src/gpu/SkGrPixelRef.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/skia/trunk/src/gpu/SkGrPixelRef.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,195 @@
+
+/*
+ * Copyright 2010 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+
+
+#include "SkGrPixelRef.h"
+#include "GrContext.h"
+#include "GrTexture.h"
+#include "SkGr.h"
+#include "SkRect.h"
+
+// since we call lockPixels recursively on fBitmap, we need a distinct mutex,
+// to avoid deadlock with the default one provided by SkPixelRef.
+SK_DECLARE_STATIC_MUTEX(gROLockPixelsPixelRefMutex);
+
+SkROLockPixelsPixelRef::SkROLockPixelsPixelRef(const SkImageInfo& info)
+    : INHERITED(info, &gROLockPixelsPixelRefMutex) {}
+
+SkROLockPixelsPixelRef::~SkROLockPixelsPixelRef() {}
+
+bool SkROLockPixelsPixelRef::onNewLockPixels(LockRec* rec) {
+    fBitmap.reset();
+//    SkDebugf("---------- calling readpixels in support of lockpixels\n");
+    if (!this->onReadPixels(&fBitmap, NULL)) {
+        SkDebugf("SkROLockPixelsPixelRef::onLockPixels failed!\n");
+        return false;
+    }
+    fBitmap.lockPixels();
+    if (NULL == fBitmap.getPixels()) {
+        return false;
+    }
+
+    rec->fPixels = fBitmap.getPixels();
+    rec->fColorTable = NULL;
+    rec->fRowBytes = fBitmap.rowBytes();
+    return true;
+}
+
+void SkROLockPixelsPixelRef::onUnlockPixels() {
+    fBitmap.unlockPixels();
+}
+
+bool SkROLockPixelsPixelRef::onLockPixelsAreWritable() const {
+    return false;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+static SkGrPixelRef* copyToTexturePixelRef(GrTexture* texture, SkBitmap::Config dstConfig,
+                                           const SkIRect* subset) {
+    if (NULL == texture) {
+        return NULL;
+    }
+    GrContext* context = texture->getContext();
+    if (NULL == context) {
+        return NULL;
+    }
+    GrTextureDesc desc;
+
+    SkIPoint pointStorage;
+    SkIPoint* topLeft;
+    if (subset != NULL) {
+        SkASSERT(SkIRect::MakeWH(texture->width(), texture->height()).contains(*subset));
+        // Create a new texture that is the size of subset.
+        desc.fWidth = subset->width();
+        desc.fHeight = subset->height();
+        pointStorage.set(subset->x(), subset->y());
+        topLeft = &pointStorage;
+    } else {
+        desc.fWidth  = texture->width();
+        desc.fHeight = texture->height();
+        topLeft = NULL;
+    }
+    desc.fFlags = kRenderTarget_GrTextureFlagBit | kNoStencil_GrTextureFlagBit;
+    desc.fConfig = SkBitmapConfig2GrPixelConfig(dstConfig);
+
+    SkImageInfo info;
+    if (!GrPixelConfig2ColorType(desc.fConfig, &info.fColorType)) {
+        return NULL;
+    }
+    info.fWidth = desc.fWidth;
+    info.fHeight = desc.fHeight;
+    info.fAlphaType = kPremul_SkAlphaType;
+
+    GrTexture* dst = context->createUncachedTexture(desc, NULL, 0);
+    if (NULL == dst) {
+        return NULL;
+    }
+
+    context->copyTexture(texture, dst->asRenderTarget(), topLeft);
+
+    // TODO: figure out if this is responsible for Chrome canvas errors
+#if 0
+    // The render texture we have created (to perform the copy) isn't fully
+    // functional (since it doesn't have a stencil buffer). Release it here
+    // so the caller doesn't try to render to it.
+    // TODO: we can undo this release when dynamic stencil buffer attach/
+    // detach has been implemented
+    dst->releaseRenderTarget();
+#endif
+
+    SkGrPixelRef* pixelRef = SkNEW_ARGS(SkGrPixelRef, (info, dst));
+    SkSafeUnref(dst);
+    return pixelRef;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+SkGrPixelRef::SkGrPixelRef(const SkImageInfo& info, GrSurface* surface,
+                           bool transferCacheLock) : INHERITED(info) {
+    // TODO: figure out if this is responsible for Chrome canvas errors
+#if 0
+    // The GrTexture has a ref to the GrRenderTarget but not vice versa.
+    // If the GrTexture exists take a ref to that (rather than the render
+    // target)
+    fSurface = surface->asTexture();
+#else
+    fSurface = NULL;
+#endif
+    if (NULL == fSurface) {
+        fSurface = surface;
+    }
+    fUnlock = transferCacheLock;
+    SkSafeRef(surface);
+
+    if (fSurface) {
+        SkASSERT(info.fWidth <= fSurface->width());
+        SkASSERT(info.fHeight <= fSurface->height());
+    }
+}
+
+SkGrPixelRef::~SkGrPixelRef() {
+    if (fUnlock) {
+        GrContext* context = fSurface->getContext();
+        GrTexture* texture = fSurface->asTexture();
+        if (NULL != context && NULL != texture) {
+            context->unlockScratchTexture(texture);
+        }
+    }
+    SkSafeUnref(fSurface);
+}
+
+GrTexture* SkGrPixelRef::getTexture() {
+    if (NULL != fSurface) {
+        return fSurface->asTexture();
+    }
+    return NULL;
+}
+
+SkPixelRef* SkGrPixelRef::deepCopy(SkBitmap::Config dstConfig, const SkIRect* subset) {
+    if (NULL == fSurface) {
+        return NULL;
+    }
+
+    // Note that when copying a render-target-backed pixel ref, we
+    // return a texture-backed pixel ref instead.  This is because
+    // render-target pixel refs are usually created in conjunction with
+    // a GrTexture owned elsewhere (e.g., SkGpuDevice), and cannot live
+    // independently of that texture.  Texture-backed pixel refs, on the other
+    // hand, own their GrTextures, and are thus self-contained.
+    return copyToTexturePixelRef(fSurface->asTexture(), dstConfig, subset);
+}
+
+bool SkGrPixelRef::onReadPixels(SkBitmap* dst, const SkIRect* subset) {
+    if (NULL == fSurface || !fSurface->isValid()) {
+        return false;
+    }
+
+    int left, top, width, height;
+    if (NULL != subset) {
+        left = subset->fLeft;
+        width = subset->width();
+        top = subset->fTop;
+        height = subset->height();
+    } else {
+        left = 0;
+        width = this->info().fWidth;
+        top = 0;
+        height = this->info().fHeight;
+    }
+    if (!dst->allocPixels(SkImageInfo::MakeN32Premul(width, height))) {
+        SkDebugf("SkGrPixelRef::onReadPixels failed to alloc bitmap for result!\n");
+        return false;
+    }
+    SkAutoLockPixels al(*dst);
+    void* buffer = dst->getPixels();
+    return fSurface->readPixels(left, top, width, height,
+                                kSkia8888_GrPixelConfig,
+                                buffer, dst->rowBytes());
+}