Here are gyp targets and stubs for compiling libcc and the webkit_compositor bindings in chromium. Everything is guarded behind the off-by-default use_libcc_for_compositor gyp variable. I haven't included the actual code here, but there are scripts to sync. I plan to land + manually sync the code into place until we're ready to flip the gyp switch.

Snapshot from r126652

BUG=

Review URL: https://chromiumcodereview.appspot.com/10828381

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@153354 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 791 insertions, 0 deletions

diff --git a/cc/TiledLayerChromium.cpp b/cc/TiledLayerChromium.cpp
new file mode 100644
index 0000000..8a6e4b9
--- /dev/null
+++ b/cc/TiledLayerChromium.cpp
@@ -0,0 +1,791 @@
+// Copyright 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "config.h"
+
+#if USE(ACCELERATED_COMPOSITING)
+
+#include "TiledLayerChromium.h"
+
+#include "CCLayerImpl.h"
+#include "CCLayerTreeHost.h"
+#include "CCOverdrawMetrics.h"
+#include "CCTextureUpdateQueue.h"
+#include "CCTiledLayerImpl.h"
+#include "GraphicsContext3D.h"
+#include "Region.h"
+#include "TextStream.h"
+#include <wtf/CurrentTime.h>
+#include <wtf/MathExtras.h>
+
+using namespace std;
+using WebKit::WebTransformationMatrix;
+
+namespace WebCore {
+
+class UpdatableTile : public CCLayerTilingData::Tile {
+    WTF_MAKE_NONCOPYABLE(UpdatableTile);
+public:
+    static PassOwnPtr<UpdatableTile> create(PassOwnPtr<LayerTextureUpdater::Texture> texture)
+    {
+        return adoptPtr(new UpdatableTile(texture));
+    }
+
+    LayerTextureUpdater::Texture* texture() { return m_texture.get(); }
+    CCPrioritizedTexture* managedTexture() { return m_texture->texture(); }
+
+    bool isDirty() const { return !dirtyRect.isEmpty(); }
+
+    // Reset update state for the current frame. This should occur before painting
+    // for all layers. Since painting one layer can invalidate another layer
+    // after it has already painted, mark all non-dirty tiles as valid before painting
+    // such that invalidations during painting won't prevent them from being pushed.
+    void resetUpdateState()
+    {
+        updateRect = IntRect();
+        occluded = false;
+        partialUpdate = false;
+        validForFrame = !isDirty();
+    }
+
+    // This promises to update the tile and therefore also guarantees the tile
+    // will be valid for this frame. dirtyRect is copied into updateRect so
+    // we can continue to track re-entrant invalidations that occur during painting.
+    void markForUpdate()
+    {
+        validForFrame = true;
+        updateRect = dirtyRect;
+        dirtyRect = IntRect();
+    }
+
+    IntRect dirtyRect;
+    IntRect updateRect;
+    bool partialUpdate;
+    bool validForFrame;
+    bool occluded;
+    bool isInUseOnImpl;
+private:
+    explicit UpdatableTile(PassOwnPtr<LayerTextureUpdater::Texture> texture)
+        : partialUpdate(false)
+        , validForFrame(false)
+        , occluded(false)
+        , isInUseOnImpl(false)
+        , m_texture(texture)
+    {
+    }
+
+    OwnPtr<LayerTextureUpdater::Texture> m_texture;
+};
+
+TiledLayerChromium::TiledLayerChromium()
+    : LayerChromium()
+    , m_textureFormat(GraphicsContext3D::INVALID_ENUM)
+    , m_skipsDraw(false)
+    , m_failedUpdate(false)
+    , m_sampledTexelFormat(LayerTextureUpdater::SampledTexelFormatInvalid)
+    , m_tilingOption(AutoTile)
+{
+    m_tiler = CCLayerTilingData::create(IntSize(), CCLayerTilingData::HasBorderTexels);
+}
+
+TiledLayerChromium::~TiledLayerChromium()
+{
+}
+
+PassOwnPtr<CCLayerImpl> TiledLayerChromium::createCCLayerImpl()
+{
+    return CCTiledLayerImpl::create(id());
+}
+
+void TiledLayerChromium::updateTileSizeAndTilingOption()
+{
+    ASSERT(layerTreeHost());
+
+    const IntSize& defaultTileSize = layerTreeHost()->settings().defaultTileSize;
+    const IntSize& maxUntiledLayerSize = layerTreeHost()->settings().maxUntiledLayerSize;
+    int layerWidth = contentBounds().width();
+    int layerHeight = contentBounds().height();
+
+    const IntSize tileSize(min(defaultTileSize.width(), layerWidth), min(defaultTileSize.height(), layerHeight));
+
+    // Tile if both dimensions large, or any one dimension large and the other
+    // extends into a second tile but the total layer area isn't larger than that
+    // of the largest possible untiled layer. This heuristic allows for long skinny layers
+    // (e.g. scrollbars) that are Nx1 tiles to minimize wasted texture space but still avoids
+    // creating very large tiles.
+    const bool anyDimensionLarge = layerWidth > maxUntiledLayerSize.width() || layerHeight > maxUntiledLayerSize.height();
+    const bool anyDimensionOneTile = (layerWidth <= defaultTileSize.width() || layerHeight <= defaultTileSize.height())
+                                      && (layerWidth * layerHeight) <= (maxUntiledLayerSize.width() * maxUntiledLayerSize.height());
+    const bool autoTiled = anyDimensionLarge && !anyDimensionOneTile;
+
+    bool isTiled;
+    if (m_tilingOption == AlwaysTile)
+        isTiled = true;
+    else if (m_tilingOption == NeverTile)
+        isTiled = false;
+    else
+        isTiled = autoTiled;
+
+    IntSize requestedSize = isTiled ? tileSize : contentBounds();
+    const int maxSize = layerTreeHost()->rendererCapabilities().maxTextureSize;
+    IntSize clampedSize = requestedSize.shrunkTo(IntSize(maxSize, maxSize));
+    setTileSize(clampedSize);
+}
+
+void TiledLayerChromium::updateBounds()
+{
+    IntSize oldBounds = m_tiler->bounds();
+    IntSize newBounds = contentBounds();
+    if (oldBounds == newBounds)
+        return;
+    m_tiler->setBounds(newBounds);
+
+    // Invalidate any areas that the new bounds exposes.
+    Region oldRegion(IntRect(IntPoint(), oldBounds));
+    Region newRegion(IntRect(IntPoint(), newBounds));
+    newRegion.subtract(oldRegion);
+    Vector<IntRect> rects = newRegion.rects();
+    for (size_t i = 0; i < rects.size(); ++i)
+        invalidateContentRect(rects[i]);
+}
+
+void TiledLayerChromium::setTileSize(const IntSize& size)
+{
+    m_tiler->setTileSize(size);
+}
+
+void TiledLayerChromium::setBorderTexelOption(CCLayerTilingData::BorderTexelOption borderTexelOption)
+{
+    m_tiler->setBorderTexelOption(borderTexelOption);
+}
+
+bool TiledLayerChromium::drawsContent() const
+{
+    if (!LayerChromium::drawsContent())
+        return false;
+
+    bool hasMoreThanOneTile = m_tiler->numTilesX() > 1 || m_tiler->numTilesY() > 1;
+    if (m_tilingOption == NeverTile && hasMoreThanOneTile)
+        return false;
+
+    return true;
+}
+
+bool TiledLayerChromium::needsContentsScale() const
+{
+    return true;
+}
+
+IntSize TiledLayerChromium::contentBounds() const
+{
+    return IntSize(lroundf(bounds().width() * contentsScale()), lroundf(bounds().height() * contentsScale()));
+}
+
+void TiledLayerChromium::setTilingOption(TilingOption tilingOption)
+{
+    m_tilingOption = tilingOption;
+}
+
+void TiledLayerChromium::setIsMask(bool isMask)
+{
+    setTilingOption(isMask ? NeverTile : AutoTile);
+}
+
+void TiledLayerChromium::pushPropertiesTo(CCLayerImpl* layer)
+{
+    LayerChromium::pushPropertiesTo(layer);
+
+    CCTiledLayerImpl* tiledLayer = static_cast<CCTiledLayerImpl*>(layer);
+
+    tiledLayer->setSkipsDraw(m_skipsDraw);
+    tiledLayer->setContentsSwizzled(m_sampledTexelFormat != LayerTextureUpdater::SampledTexelFormatRGBA);
+    tiledLayer->setTilingData(*m_tiler);
+    Vector<UpdatableTile*> invalidTiles;
+
+    for (CCLayerTilingData::TileMap::const_iterator iter = m_tiler->tiles().begin(); iter != m_tiler->tiles().end(); ++iter) {
+        int i = iter->first.first;
+        int j = iter->first.second;
+        UpdatableTile* tile = static_cast<UpdatableTile*>(iter->second.get());
+        // FIXME: This should not ever be null.
+        if (!tile)
+            continue;
+        tile->isInUseOnImpl = false;
+        if (!tile->managedTexture()->haveBackingTexture()) {
+            invalidTiles.append(tile);
+            continue;
+        }
+        if (!tile->validForFrame)
+            continue;
+
+        tiledLayer->pushTileProperties(i, j, tile->managedTexture()->resourceId(), tile->opaqueRect());
+        tile->isInUseOnImpl = true;
+    }
+    for (Vector<UpdatableTile*>::const_iterator iter = invalidTiles.begin(); iter != invalidTiles.end(); ++iter)
+        m_tiler->takeTile((*iter)->i(), (*iter)->j());
+}
+
+CCPrioritizedTextureManager* TiledLayerChromium::textureManager() const
+{
+    if (!layerTreeHost())
+        return 0;
+    return layerTreeHost()->contentsTextureManager();
+}
+
+void TiledLayerChromium::setLayerTreeHost(CCLayerTreeHost* host)
+{
+    if (host && host != layerTreeHost()) {
+        for (CCLayerTilingData::TileMap::const_iterator iter = m_tiler->tiles().begin(); iter != m_tiler->tiles().end(); ++iter) {
+            UpdatableTile* tile = static_cast<UpdatableTile*>(iter->second.get());
+            // FIXME: This should not ever be null.
+            if (!tile)
+                continue;
+            tile->managedTexture()->setTextureManager(host->contentsTextureManager());
+        }
+    }
+    LayerChromium::setLayerTreeHost(host);
+}
+
+UpdatableTile* TiledLayerChromium::tileAt(int i, int j) const
+{
+    return static_cast<UpdatableTile*>(m_tiler->tileAt(i, j));
+}
+
+UpdatableTile* TiledLayerChromium::createTile(int i, int j)
+{
+    createTextureUpdaterIfNeeded();
+
+    OwnPtr<UpdatableTile> tile(UpdatableTile::create(textureUpdater()->createTexture(textureManager())));
+    tile->managedTexture()->setDimensions(m_tiler->tileSize(), m_textureFormat);
+
+    UpdatableTile* addedTile = tile.get();
+    m_tiler->addTile(tile.release(), i, j);
+
+    addedTile->dirtyRect = m_tiler->tileRect(addedTile);
+
+    // Temporary diagnostic crash.
+    if (!addedTile)
+        CRASH();
+    if (!tileAt(i, j))
+        CRASH();
+
+    return addedTile;
+}
+
+void TiledLayerChromium::setNeedsDisplayRect(const FloatRect& dirtyRect)
+{
+    float contentsWidthScale = static_cast<float>(contentBounds().width()) / bounds().width();
+    float contentsHeightScale = static_cast<float>(contentBounds().height()) / bounds().height();
+    FloatRect scaledDirtyRect(dirtyRect);
+    scaledDirtyRect.scale(contentsWidthScale, contentsHeightScale);
+    IntRect dirty = enclosingIntRect(scaledDirtyRect);
+    invalidateContentRect(dirty);
+    LayerChromium::setNeedsDisplayRect(dirtyRect);
+}
+
+void TiledLayerChromium::setUseLCDText(bool useLCDText)
+{
+    LayerChromium::setUseLCDText(useLCDText);
+
+    CCLayerTilingData::BorderTexelOption borderTexelOption;
+#if OS(ANDROID)
+    // Always want border texels and GL_LINEAR due to pinch zoom.
+    borderTexelOption = CCLayerTilingData::HasBorderTexels;
+#else
+    borderTexelOption = useLCDText ? CCLayerTilingData::NoBorderTexels : CCLayerTilingData::HasBorderTexels;
+#endif
+    setBorderTexelOption(borderTexelOption);
+}
+
+void TiledLayerChromium::invalidateContentRect(const IntRect& contentRect)
+{
+    updateBounds();
+    if (m_tiler->isEmpty() || contentRect.isEmpty() || m_skipsDraw)
+        return;
+
+    for (CCLayerTilingData::TileMap::const_iterator iter = m_tiler->tiles().begin(); iter != m_tiler->tiles().end(); ++iter) {
+        UpdatableTile* tile = static_cast<UpdatableTile*>(iter->second.get());
+        ASSERT(tile);
+        // FIXME: This should not ever be null.
+        if (!tile)
+            continue;
+        IntRect bound = m_tiler->tileRect(tile);
+        bound.intersect(contentRect);
+        tile->dirtyRect.unite(bound);
+    }
+}
+
+// Returns true if tile is dirty and only part of it needs to be updated.
+bool TiledLayerChromium::tileOnlyNeedsPartialUpdate(UpdatableTile* tile)
+{
+    return !tile->dirtyRect.contains(m_tiler->tileRect(tile));
+}
+
+// Dirty tiles with valid textures needs buffered update to guarantee that
+// we don't modify textures currently used for drawing by the impl thread.
+bool TiledLayerChromium::tileNeedsBufferedUpdate(UpdatableTile* tile)
+{
+    if (!tile->managedTexture()->haveBackingTexture())
+        return false;
+
+    if (!tile->isDirty())
+        return false;
+
+    if (!tile->isInUseOnImpl)
+        return false;
+
+    return true;
+}
+
+
+bool TiledLayerChromium::updateTiles(int left, int top, int right, int bottom, CCTextureUpdateQueue& queue, const CCOcclusionTracker* occlusion, CCRenderingStats& stats, bool& didPaint)
+{
+    didPaint = false;
+    createTextureUpdaterIfNeeded();
+
+    bool ignoreOcclusions = !occlusion;
+    if (!haveTexturesForTiles(left, top, right, bottom, ignoreOcclusions)) {
+        m_failedUpdate = true;
+        return false;
+    }
+
+    IntRect paintRect = markTilesForUpdate(left, top, right, bottom, ignoreOcclusions);
+
+    if (occlusion)
+        occlusion->overdrawMetrics().didPaint(paintRect);
+
+    if (paintRect.isEmpty())
+        return true;
+
+    didPaint = true;
+    updateTileTextures(paintRect, left, top, right, bottom, queue, occlusion, stats);
+    return true;
+}
+
+void TiledLayerChromium::markOcclusionsAndRequestTextures(int left, int top, int right, int bottom, const CCOcclusionTracker* occlusion)
+{
+    // There is some difficult dependancies between occlusions, recording occlusion metrics
+    // and requesting memory so those are encapsulated in this function:
+    // - We only want to call requestLate on unoccluded textures (to preserve
+    //   memory for other layers when near OOM).
+    // - We only want to record occlusion metrics if all memory requests succeed.
+
+    int occludedTileCount = 0;
+    bool succeeded = true;
+    for (int j = top; j <= bottom; ++j) {
+        for (int i = left; i <= right; ++i) {
+            UpdatableTile* tile = tileAt(i, j);
+            ASSERT(tile); // Did setTexturePriorities get skipped?
+            // FIXME: This should not ever be null.
+            if (!tile)
+                continue;
+            ASSERT(!tile->occluded); // Did resetUpdateState get skipped? Are we doing more than one occlusion pass?
+            IntRect visibleTileRect = intersection(m_tiler->tileBounds(i, j), visibleContentRect());
+            if (occlusion && occlusion->occluded(this, visibleTileRect)) {
+                tile->occluded = true;
+                occludedTileCount++;
+            } else {
+                succeeded &= tile->managedTexture()->requestLate();
+            }
+        }
+    }
+
+    if (!succeeded)
+        return;
+
+    // FIXME: Remove the loop and just pass the count!
+    for (int i = 0; i < occludedTileCount; i++)
+        occlusion->overdrawMetrics().didCullTileForUpload();
+}
+
+bool TiledLayerChromium::haveTexturesForTiles(int left, int top, int right, int bottom, bool ignoreOcclusions)
+{
+    for (int j = top; j <= bottom; ++j) {
+        for (int i = left; i <= right; ++i) {
+            UpdatableTile* tile = tileAt(i, j);
+            ASSERT(tile); // Did setTexturePriorites get skipped?
+            // FIXME: This should not ever be null.
+            if (!tile)
+                continue;
+
+            // Ensure the entire tile is dirty if we don't have the texture.
+            if (!tile->managedTexture()->haveBackingTexture())
+                tile->dirtyRect = m_tiler->tileRect(tile);
+
+            // If using occlusion and the visible region of the tile is occluded,
+            // don't reserve a texture or update the tile.
+            if (tile->occluded && !ignoreOcclusions)
+                continue;
+
+            if (!tile->managedTexture()->canAcquireBackingTexture())
+                return false;
+        }
+    }
+    return true;
+}
+
+IntRect TiledLayerChromium::markTilesForUpdate(int left, int top, int right, int bottom, bool ignoreOcclusions)
+{
+    IntRect paintRect;
+    for (int j = top; j <= bottom; ++j) {
+        for (int i = left; i <= right; ++i) {
+            UpdatableTile* tile = tileAt(i, j);
+            ASSERT(tile); // Did setTexturePriorites get skipped?
+            // FIXME: This should not ever be null.
+            if (!tile)
+                continue;
+            if (tile->occluded && !ignoreOcclusions)
+                continue;
+            paintRect.unite(tile->dirtyRect);
+            tile->markForUpdate();
+        }
+    }
+    return paintRect;
+}
+
+void TiledLayerChromium::updateTileTextures(const IntRect& paintRect, int left, int top, int right, int bottom, CCTextureUpdateQueue& queue, const CCOcclusionTracker* occlusion, CCRenderingStats& stats)
+{
+    // The updateRect should be in layer space. So we have to convert the paintRect from content space to layer space.
+    m_updateRect = FloatRect(paintRect);
+    float widthScale = bounds().width() / static_cast<float>(contentBounds().width());
+    float heightScale = bounds().height() / static_cast<float>(contentBounds().height());
+    m_updateRect.scale(widthScale, heightScale);
+
+    // Calling prepareToUpdate() calls into WebKit to paint, which may have the side
+    // effect of disabling compositing, which causes our reference to the texture updater to be deleted.
+    // However, we can't free the memory backing the SkCanvas until the paint finishes,
+    // so we grab a local reference here to hold the updater alive until the paint completes.
+    RefPtr<LayerTextureUpdater> protector(textureUpdater());
+    IntRect paintedOpaqueRect;
+    textureUpdater()->prepareToUpdate(paintRect, m_tiler->tileSize(), 1 / widthScale, 1 / heightScale, paintedOpaqueRect, stats);
+
+    for (int j = top; j <= bottom; ++j) {
+        for (int i = left; i <= right; ++i) {
+            UpdatableTile* tile = tileAt(i, j);
+            ASSERT(tile); // Did setTexturePriorites get skipped?
+            // FIXME: This should not ever be null.
+            if (!tile)
+                continue;
+
+            IntRect tileRect = m_tiler->tileBounds(i, j);
+
+            // Use updateRect as the above loop copied the dirty rect for this frame to updateRect.
+            const IntRect& dirtyRect = tile->updateRect;
+            if (dirtyRect.isEmpty())
+                continue;
+
+            // Save what was painted opaque in the tile. Keep the old area if the paint didn't touch it, and didn't paint some
+            // other part of the tile opaque.
+            IntRect tilePaintedRect = intersection(tileRect, paintRect);
+            IntRect tilePaintedOpaqueRect = intersection(tileRect, paintedOpaqueRect);
+            if (!tilePaintedRect.isEmpty()) {
+                IntRect paintInsideTileOpaqueRect = intersection(tile->opaqueRect(), tilePaintedRect);
+                bool paintInsideTileOpaqueRectIsNonOpaque = !tilePaintedOpaqueRect.contains(paintInsideTileOpaqueRect);
+                bool opaquePaintNotInsideTileOpaqueRect = !tilePaintedOpaqueRect.isEmpty() && !tile->opaqueRect().contains(tilePaintedOpaqueRect);
+
+                if (paintInsideTileOpaqueRectIsNonOpaque || opaquePaintNotInsideTileOpaqueRect)
+                    tile->setOpaqueRect(tilePaintedOpaqueRect);
+            }
+
+            // sourceRect starts as a full-sized tile with border texels included.
+            IntRect sourceRect = m_tiler->tileRect(tile);
+            sourceRect.intersect(dirtyRect);
+            // Paint rect not guaranteed to line up on tile boundaries, so
+            // make sure that sourceRect doesn't extend outside of it.
+            sourceRect.intersect(paintRect);
+
+            tile->updateRect = sourceRect;
+
+            if (sourceRect.isEmpty())
+                continue;
+
+            tile->texture()->prepareRect(sourceRect, stats);
+            if (occlusion)
+                occlusion->overdrawMetrics().didUpload(WebTransformationMatrix(), sourceRect, tile->opaqueRect());
+
+            const IntPoint anchor = m_tiler->tileRect(tile).location();
+
+            // Calculate tile-space rectangle to upload into.
+            IntSize destOffset(sourceRect.x() - anchor.x(), sourceRect.y() - anchor.y());
+            if (destOffset.width() < 0)
+                CRASH();
+            if (destOffset.height() < 0)
+                CRASH();
+
+            // Offset from paint rectangle to this tile's dirty rectangle.
+            IntPoint paintOffset(sourceRect.x() - paintRect.x(), sourceRect.y() - paintRect.y());
+            if (paintOffset.x() < 0)
+                CRASH();
+            if (paintOffset.y() < 0)
+                CRASH();
+            if (paintOffset.x() + sourceRect.width() > paintRect.width())
+                CRASH();
+            if (paintOffset.y() + sourceRect.height() > paintRect.height())
+                CRASH();
+
+            TextureUploader::Parameters upload = { tile->texture(), sourceRect, destOffset };
+            if (tile->partialUpdate)
+                queue.appendPartialUpload(upload);
+            else
+                queue.appendFullUpload(upload);
+        }
+    }
+}
+
+namespace {
+// This picks a small animated layer to be anything less than one viewport. This
+// is specifically for page transitions which are viewport-sized layers. The extra
+// 64 pixels is due to these layers being slightly larger than the viewport in some cases.
+bool isSmallAnimatedLayer(TiledLayerChromium* layer)
+{
+    if (!layer->drawTransformIsAnimating() && !layer->screenSpaceTransformIsAnimating())
+        return false;
+    IntSize viewportSize = layer->layerTreeHost() ? layer->layerTreeHost()->deviceViewportSize() : IntSize();
+    IntRect contentRect(IntPoint::zero(), layer->contentBounds());
+    return contentRect.width() <= viewportSize.width() + 64
+        && contentRect.height() <= viewportSize.height() + 64;
+}
+
+// FIXME: Remove this and make this based on distance once distance can be calculated
+// for offscreen layers. For now, prioritize all small animated layers after 512
+// pixels of pre-painting.
+void setPriorityForTexture(const CCPriorityCalculator& priorityCalc,
+                           const IntRect& visibleRect,
+                           const IntRect& tileRect,
+                           bool drawsToRoot,
+                           bool isSmallAnimatedLayer,
+                           CCPrioritizedTexture* texture)
+{
+    int priority = CCPriorityCalculator::lowestPriority();
+    if (!visibleRect.isEmpty())
+        priority = priorityCalc.priorityFromDistance(visibleRect, tileRect, drawsToRoot);
+    if (isSmallAnimatedLayer)
+        priority = CCPriorityCalculator::maxPriority(priority, priorityCalc.priorityFromDistance(512, drawsToRoot));
+    if (priority != CCPriorityCalculator::lowestPriority())
+        texture->setRequestPriority(priority);
+}
+}
+
+void TiledLayerChromium::setTexturePriorities(const CCPriorityCalculator& priorityCalc)
+{
+    updateBounds();
+    resetUpdateState();
+
+    if (m_tiler->hasEmptyBounds())
+        return;
+
+    bool drawsToRoot = !renderTarget()->parent();
+    bool smallAnimatedLayer = isSmallAnimatedLayer(this);
+
+    // Minimally create the tiles in the desired pre-paint rect.
+    IntRect createTilesRect = idlePaintRect();
+    if (!createTilesRect.isEmpty()) {
+        int left, top, right, bottom;
+        m_tiler->contentRectToTileIndices(createTilesRect, left, top, right, bottom);
+        for (int j = top; j <= bottom; ++j) {
+            for (int i = left; i <= right; ++i) {
+                if (!tileAt(i, j))
+                    createTile(i, j);
+            }
+        }
+    }
+
+    // Also, minimally create all tiles for small animated layers and also
+    // double-buffer them since we have limited their size to be reasonable.
+    IntRect doubleBufferedRect = visibleContentRect();
+    if (smallAnimatedLayer)
+        doubleBufferedRect = IntRect(IntPoint::zero(), contentBounds());
+
+    // Create additional textures for double-buffered updates when needed.
+    // These textures must stay alive while the updated textures are incrementally
+    // uploaded, swapped atomically via pushProperties, and finally deleted
+    // after the commit is complete, after which they can be recycled.
+    if (!doubleBufferedRect.isEmpty()) {
+        int left, top, right, bottom;
+        m_tiler->contentRectToTileIndices(doubleBufferedRect, left, top, right, bottom);
+        for (int j = top; j <= bottom; ++j) {
+            for (int i = left; i <= right; ++i) {
+                UpdatableTile* tile = tileAt(i, j);
+                if (!tile)
+                    tile = createTile(i, j);
+                // We need an additional texture if the tile needs a buffered-update and it's not a partial update.
+                // FIXME: Decide if partial update should be allowed based on cost
+                // of update. https://bugs.webkit.org/show_bug.cgi?id=77376
+                if (!layerTreeHost() || !layerTreeHost()->bufferedUpdates() || !tileNeedsBufferedUpdate(tile))
+                    continue;
+                if (tileOnlyNeedsPartialUpdate(tile) && layerTreeHost()->requestPartialTextureUpdate()) {
+                    tile->partialUpdate = true;
+                    continue;
+                }
+
+                IntRect tileRect = m_tiler->tileRect(tile);
+                tile->dirtyRect = tileRect;
+                LayerTextureUpdater::Texture* backBuffer = tile->texture();
+                setPriorityForTexture(priorityCalc, visibleContentRect(), tile->dirtyRect, drawsToRoot, smallAnimatedLayer, backBuffer->texture());
+                OwnPtr<CCPrioritizedTexture> frontBuffer = CCPrioritizedTexture::create(backBuffer->texture()->textureManager(),
+                                                                                        backBuffer->texture()->size(),
+                                                                                        backBuffer->texture()->format());
+                // Swap backBuffer into frontBuffer and add it to delete after commit queue.
+                backBuffer->swapTextureWith(frontBuffer);
+                layerTreeHost()->deleteTextureAfterCommit(frontBuffer.release());
+            }
+        }
+    }
+
+    // Now update priorities on all tiles we have in the layer, no matter where they are.
+    for (CCLayerTilingData::TileMap::const_iterator iter = m_tiler->tiles().begin(); iter != m_tiler->tiles().end(); ++iter) {
+        UpdatableTile* tile = static_cast<UpdatableTile*>(iter->second.get());
+        // FIXME: This should not ever be null.
+        if (!tile)
+            continue;
+        IntRect tileRect = m_tiler->tileRect(tile);
+        setPriorityForTexture(priorityCalc, visibleContentRect(), tileRect, drawsToRoot, smallAnimatedLayer, tile->managedTexture());
+    }
+}
+
+Region TiledLayerChromium::visibleContentOpaqueRegion() const
+{
+    if (m_skipsDraw)
+        return Region();
+    if (opaque())
+        return visibleContentRect();
+    return m_tiler->opaqueRegionInContentRect(visibleContentRect());
+}
+
+void TiledLayerChromium::resetUpdateState()
+{
+    m_skipsDraw = false;
+    m_failedUpdate = false;
+
+    CCLayerTilingData::TileMap::const_iterator end = m_tiler->tiles().end();
+    for (CCLayerTilingData::TileMap::const_iterator iter = m_tiler->tiles().begin(); iter != end; ++iter) {
+        UpdatableTile* tile = static_cast<UpdatableTile*>(iter->second.get());
+        // FIXME: This should not ever be null.
+        if (!tile)
+            continue;
+        tile->resetUpdateState();
+    }
+}
+
+void TiledLayerChromium::update(CCTextureUpdateQueue& queue, const CCOcclusionTracker* occlusion, CCRenderingStats& stats)
+{
+    ASSERT(!m_skipsDraw && !m_failedUpdate); // Did resetUpdateState get skipped?
+    updateBounds();
+    if (m_tiler->hasEmptyBounds() || !drawsContent())
+        return;
+
+    bool didPaint = false;
+
+    // Animation pre-paint. If the layer is small, try to paint it all
+    // immediately whether or not it is occluded, to avoid paint/upload
+    // hiccups while it is animating.
+    if (isSmallAnimatedLayer(this)) {
+        int left, top, right, bottom;
+        m_tiler->contentRectToTileIndices(IntRect(IntPoint::zero(), contentBounds()), left, top, right, bottom);
+        updateTiles(left, top, right, bottom, queue, 0, stats, didPaint);
+        if (didPaint)
+            return;
+        // This was an attempt to paint the entire layer so if we fail it's okay,
+        // just fallback on painting visible etc. below.
+        m_failedUpdate = false;
+    }
+
+    if (visibleContentRect().isEmpty())
+        return;
+
+    // Visible painting. First occlude visible tiles and paint the non-occluded tiles.
+    int left, top, right, bottom;
+    m_tiler->contentRectToTileIndices(visibleContentRect(), left, top, right, bottom);
+    markOcclusionsAndRequestTextures(left, top, right, bottom, occlusion);
+    m_skipsDraw = !updateTiles(left, top, right, bottom, queue, occlusion, stats, didPaint);
+    if (m_skipsDraw)
+        m_tiler->reset();
+    if (m_skipsDraw || didPaint)
+        return;
+
+    // If we have already painting everything visible. Do some pre-painting while idle.
+    IntRect idlePaintContentRect = idlePaintRect();
+    if (idlePaintContentRect.isEmpty())
+        return;
+
+    // Prepaint anything that was occluded but inside the layer's visible region.
+    if (!updateTiles(left, top, right, bottom, queue, 0, stats, didPaint) || didPaint)
+        return;
+
+    int prepaintLeft, prepaintTop, prepaintRight, prepaintBottom;
+    m_tiler->contentRectToTileIndices(idlePaintContentRect, prepaintLeft, prepaintTop, prepaintRight, prepaintBottom);
+
+    // Then expand outwards from the visible area until we find a dirty row or column to update.
+    while (left > prepaintLeft || top > prepaintTop || right < prepaintRight || bottom < prepaintBottom) {
+        if (bottom < prepaintBottom) {
+            ++bottom;
+            if (!updateTiles(left, bottom, right, bottom, queue, 0, stats, didPaint) || didPaint)
+                return;
+        }
+        if (top > prepaintTop) {
+            --top;
+            if (!updateTiles(left, top, right, top, queue, 0, stats, didPaint) || didPaint)
+                return;
+        }
+        if (left > prepaintLeft) {
+            --left;
+            if (!updateTiles(left, top, left, bottom, queue, 0, stats, didPaint) || didPaint)
+                return;
+        }
+        if (right < prepaintRight) {
+            ++right;
+            if (!updateTiles(right, top, right, bottom, queue, 0, stats, didPaint) || didPaint)
+                return;
+        }
+    }
+}
+
+bool TiledLayerChromium::needsIdlePaint()
+{
+    // Don't trigger more paints if we failed (as we'll just fail again).
+    if (m_failedUpdate || visibleContentRect().isEmpty() || m_tiler->hasEmptyBounds() || !drawsContent())
+        return false;
+
+    IntRect idlePaintContentRect = idlePaintRect();
+    if (idlePaintContentRect.isEmpty())
+        return false;
+
+    int left, top, right, bottom;
+    m_tiler->contentRectToTileIndices(idlePaintContentRect, left, top, right, bottom);
+
+    for (int j = top; j <= bottom; ++j) {
+        for (int i = left; i <= right; ++i) {
+            UpdatableTile* tile = tileAt(i, j);
+            ASSERT(tile); // Did setTexturePriorities get skipped?
+            if (!tile)
+                continue;
+
+            bool updated = !tile->updateRect.isEmpty();
+            bool canAcquire = tile->managedTexture()->canAcquireBackingTexture();
+            bool dirty = tile->isDirty() || !tile->managedTexture()->haveBackingTexture();
+            if (!updated && canAcquire && dirty)
+                return true;
+        }
+    }
+    return false;
+}
+
+IntRect TiledLayerChromium::idlePaintRect()
+{
+    // Don't inflate an empty rect.
+    if (visibleContentRect().isEmpty())
+        return IntRect();
+
+    // FIXME: This can be made a lot larger now! We should increase
+    //        this slowly while insuring it doesn't cause any perf issues.
+    IntRect prepaintRect = visibleContentRect();
+    prepaintRect.inflateX(m_tiler->tileSize().width());
+    prepaintRect.inflateY(m_tiler->tileSize().height() * 2);
+    IntRect contentRect(IntPoint::zero(), contentBounds());
+    prepaintRect.intersect(contentRect);
+
+    return prepaintRect;
+}
+
+}
+#endif // USE(ACCELERATED_COMPOSITING)