diff -r 000000000000 -r 6474c204b198 gfx/skia/trunk/src/core/SkPictureStateTree.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/skia/trunk/src/core/SkPictureStateTree.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,186 @@
+
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkPictureStateTree.h"
+#include "SkCanvas.h"
+
+SkPictureStateTree::SkPictureStateTree()
+    : fAlloc(2048)
+    , fLastRestoredNode(NULL)
+    , fStateStack(sizeof(Draw), 16) {
+    fRootMatrix.reset();
+    fRoot.fParent = NULL;
+    fRoot.fMatrix = &fRootMatrix;
+    fRoot.fFlags = Node::kSave_Flag;
+    fRoot.fOffset = 0;
+    fRoot.fLevel = 0;
+    fCurrentState.fNode = &fRoot;
+    fCurrentState.fMatrix = &fRootMatrix;
+    *static_cast<Draw*>(fStateStack.push_back()) = fCurrentState;
+}
+
+SkPictureStateTree::~SkPictureStateTree() {
+}
+
+SkPictureStateTree::Draw* SkPictureStateTree::appendDraw(size_t offset) {
+    Draw* draw = static_cast<Draw*>(fAlloc.allocThrow(sizeof(Draw)));
+    *draw = fCurrentState;
+    draw->fOffset = SkToU32(offset);
+    return draw;
+}
+
+void SkPictureStateTree::appendSave() {
+    *static_cast<Draw*>(fStateStack.push_back()) = fCurrentState;
+    fCurrentState.fNode->fFlags |= Node::kSave_Flag;
+}
+
+void SkPictureStateTree::appendSaveLayer(size_t offset) {
+    *static_cast<Draw*>(fStateStack.push_back()) = fCurrentState;
+    this->appendNode(offset);
+    fCurrentState.fNode->fFlags |= Node::kSaveLayer_Flag;
+}
+
+void SkPictureStateTree::saveCollapsed() {
+    SkASSERT(NULL != fLastRestoredNode);
+    SkASSERT(SkToBool(fLastRestoredNode->fFlags & \
+        (Node::kSaveLayer_Flag | Node::kSave_Flag)));
+    SkASSERT(fLastRestoredNode->fParent == fCurrentState.fNode);
+    // The structure of the tree is not modified here. We just turn off
+    // the save or saveLayer flag to prevent the iterator from making state
+    // changing calls on the playback canvas when traversing a save or
+    // saveLayerNode node.
+    fLastRestoredNode->fFlags = 0;
+}
+
+void SkPictureStateTree::appendRestore() {
+    fLastRestoredNode = fCurrentState.fNode;
+    fCurrentState = *static_cast<Draw*>(fStateStack.back());
+    fStateStack.pop_back();
+}
+
+void SkPictureStateTree::appendTransform(const SkMatrix& trans) {
+    SkMatrix* m = static_cast<SkMatrix*>(fAlloc.allocThrow(sizeof(SkMatrix)));
+    *m = trans;
+    fCurrentState.fMatrix = m;
+}
+
+void SkPictureStateTree::appendClip(size_t offset) {
+    this->appendNode(offset);
+}
+
+SkPictureStateTree::Iterator SkPictureStateTree::getIterator(const SkTDArray<void*>& draws,
+                                                             SkCanvas* canvas) {
+    return Iterator(draws, canvas, &fRoot);
+}
+
+void SkPictureStateTree::appendNode(size_t offset) {
+    Node* n = static_cast<Node*>(fAlloc.allocThrow(sizeof(Node)));
+    n->fOffset = SkToU32(offset);
+    n->fFlags = 0;
+    n->fParent = fCurrentState.fNode;
+    n->fLevel = fCurrentState.fNode->fLevel + 1;
+    n->fMatrix = fCurrentState.fMatrix;
+    fCurrentState.fNode = n;
+}
+
+SkPictureStateTree::Iterator::Iterator(const SkTDArray<void*>& draws, SkCanvas* canvas, Node* root)
+    : fDraws(&draws)
+    , fCanvas(canvas)
+    , fCurrentNode(root)
+    , fPlaybackMatrix(canvas->getTotalMatrix())
+    , fCurrentMatrix(NULL)
+    , fPlaybackIndex(0)
+    , fSave(false)
+    , fValid(true) {
+}
+
+uint32_t SkPictureStateTree::Iterator::draw() {
+    SkASSERT(this->isValid());
+    if (fPlaybackIndex >= fDraws->count()) {
+        // restore back to where we started
+        fCanvas->setMatrix(fPlaybackMatrix);
+        if (fCurrentNode->fFlags & Node::kSaveLayer_Flag) { fCanvas->restore(); }
+        fCurrentNode = fCurrentNode->fParent;
+        while (NULL != fCurrentNode) {
+            if (fCurrentNode->fFlags & Node::kSave_Flag) { fCanvas->restore(); }
+            if (fCurrentNode->fFlags & Node::kSaveLayer_Flag) { fCanvas->restore(); }
+            fCurrentNode = fCurrentNode->fParent;
+        }
+        return kDrawComplete;
+    }
+
+    Draw* draw = static_cast<Draw*>((*fDraws)[fPlaybackIndex]);
+    Node* targetNode = draw->fNode;
+
+    if (fSave) {
+        fCanvas->save(SkCanvas::kClip_SaveFlag);
+        fSave = false;
+    }
+
+    if (fCurrentNode != targetNode) {
+        // If we're not at the target and we don't have a list of nodes to get there, we need to
+        // figure out the path from our current node, to the target
+        if (fNodes.count() == 0) {
+            // Trace back up to a common ancestor, restoring to get our current state to match that
+            // of the ancestor, and saving a list of nodes whose state we need to apply to get to
+            // the target (we can restore up to the ancestor immediately, but we'll need to return
+            // an offset for each node on the way down to the target, to apply the desired clips and
+            // saveLayers, so it may take several draw() calls before the next draw actually occurs)
+            Node* tmp = fCurrentNode;
+            Node* ancestor = targetNode;
+            while (tmp != ancestor) {
+                uint16_t currentLevel = tmp->fLevel;
+                uint16_t targetLevel = ancestor->fLevel;
+                if (currentLevel >= targetLevel) {
+                    if (tmp != fCurrentNode && tmp->fFlags & Node::kSave_Flag) { fCanvas->restore(); }
+                    if (tmp->fFlags & Node::kSaveLayer_Flag) { fCanvas->restore(); }
+                    tmp = tmp->fParent;
+                }
+                if (currentLevel <= targetLevel) {
+                    fNodes.push(ancestor);
+                    ancestor = ancestor->fParent;
+                }
+            }
+
+            if (ancestor->fFlags & Node::kSave_Flag) {
+                if (fCurrentNode != ancestor) { fCanvas->restore(); }
+                if (targetNode != ancestor) { fCanvas->save(SkCanvas::kClip_SaveFlag); }
+            }
+            fCurrentNode = ancestor;
+        }
+
+        // If we're not at the target node yet, we'll need to return an offset to make the caller
+        // apply the next clip or saveLayer.
+        if (fCurrentNode != targetNode) {
+            if (fCurrentMatrix != fNodes.top()->fMatrix) {
+                fCurrentMatrix = fNodes.top()->fMatrix;
+                SkMatrix tmp = *fNodes.top()->fMatrix;
+                tmp.postConcat(fPlaybackMatrix);
+                fCanvas->setMatrix(tmp);
+            }
+            uint32_t offset = fNodes.top()->fOffset;
+            fCurrentNode = fNodes.top();
+            fSave = fCurrentNode != targetNode && fCurrentNode->fFlags & Node::kSave_Flag;
+            fNodes.pop();
+            return offset;
+        }
+    }
+
+    // If we got this far, the clip/saveLayer state is all set, so we can proceed to set the matrix
+    // for the draw, and return its offset.
+
+    if (fCurrentMatrix != draw->fMatrix) {
+        SkMatrix tmp = *draw->fMatrix;
+        tmp.postConcat(fPlaybackMatrix);
+        fCanvas->setMatrix(tmp);
+        fCurrentMatrix = draw->fMatrix;
+    }
+
+    ++fPlaybackIndex;
+    return draw->fOffset;
+}