cc: Handle directly composited images in impl-side painting

cc/picture_image_layer.cc

Index: cc/picture_image_layer.cc
diff --git a/cc/picture_image_layer.cc b/cc/picture_image_layer.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b87c6e6d9cbbd0304037a69f7b3626c048b1eb1e
--- /dev/null
+++ b/cc/picture_image_layer.cc
@@ -0,0 +1,70 @@
+// Copyright 2010 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 "cc/picture_image_layer.h"
+
+#include "third_party/skia/include/core/SkCanvas.h"
+
+namespace cc {
+
+scoped_refptr<PictureImageLayer> PictureImageLayer::create()
+{
+  return make_scoped_refptr(new PictureImageLayer());
+}
+
+PictureImageLayer::PictureImageLayer()
+    : PictureLayer(this)
+{
+}
+
+PictureImageLayer::~PictureImageLayer()
+{
+  clearClient();
+}
+
+void PictureImageLayer::setBitmap(const SkBitmap& bitmap)
+{
+  // setBitmap() currently gets called whenever there is any
+  // style change that affects the layer even if that change doesn't
+  // affect the actual contents of the image (e.g. a CSS animation).
+  // With this check in place we avoid unecessary texture uploads.
+  if (bitmap.pixelRef() && bitmap.pixelRef() == bitmap_.pixelRef())
+      return;
+
+  bitmap_ = bitmap;
+  setNeedsDisplay();
+}
+
+void PictureImageLayer::update(
+    ResourceUpdateQueue& queue,
+    const OcclusionTracker* tracker,
+    RenderingStats& stats) {
+  if (bounds() != bounds_) {
+    // Pictures are recorded in layer space, so if the layer size changes,
+    // then the picture needs to be re-scaled, as a directly composited image
+    // always fills its entire layer bounds.  This could be improved by
+    // recording pictures of images at their actual resolution somehow.
+    bounds_ = bounds();
+    setNeedsDisplay();
+  }
+  PictureLayer::update(queue, tracker, stats);
+}
+
+void PictureImageLayer::paintContents(
+    SkCanvas* canvas,
+    const gfx::Rect& clip,
+    gfx::RectF& opaque) {
+  if (!bitmap_.width() || !bitmap_.height())
+    return;
+
+  SkScalar content_to_layer_scale_x = SkFloatToScalar(
+      static_cast<float>(bounds().width()) / bitmap_.width());
+  SkScalar content_to_layer_scale_y = SkFloatToScalar(
+      static_cast<float>(bounds().height()) / bitmap_.height());
+  canvas->scale(content_to_layer_scale_x, content_to_layer_scale_y);
+
+  canvas->drawBitmap(bitmap_, 0, 0);
+}
+
+}  // namespace cc