Implement the logic to kick off image decoding jobs for TileManager

cc/picture.cc

Index: cc/picture.cc
diff --git a/cc/picture.cc b/cc/picture.cc
index 47d1b23d59d04e808837d423d7a9fdccaf0fd2b2..f190430a79844dc5f4f816773f7d88f47ec69f3c 100644
--- a/cc/picture.cc
+++ b/cc/picture.cc
@@ -7,8 +7,15 @@
 #include "cc/picture.h"
 #include "cc/rendering_stats.h"
 #include "third_party/skia/include/core/SkCanvas.h"
+#include "third_party/skia/include/core/SkData.h"
+#include "third_party/skia/include/utils/SkPictureUtils.h"
 #include "ui/gfx/rect_conversions.h"
 
+namespace {
+// URI label for a lazily decoded SkPixelRef.
+const char labelLazyDecoded[] = "lazy";
+}
+
 namespace cc {
 
 scoped_refptr<Picture> Picture::Create(gfx::Rect layer_rect) {
@@ -88,4 +95,32 @@ void Picture::Raster(SkCanvas* canvas) {
   canvas->restore();
 }
 
+void Picture::GatherPixelRefs(const gfx::Rect& rect,
+                              std::vector<SkPixelRef*>& result) {

[reveman, 2012/12/10 17:58:12]

should this be a std::vector<LazyPixelRef*> and we do the cast from SkPixelRef*
to LazyPixelRef* here rather than in the tile manager?

[qinmin, 2012/12/10 22:52:51]

Done.

+  DCHECK(picture_);
+  SkData* pixel_refs = SkPictureUtils::GatherPixelRefs(
+      picture_.get(), SkRect::MakeXYWH(rect.x(),
+                                       rect.y(),
+                                       rect.width(),
+                                       rect.height()));
+  if (!pixel_refs)
+    return;
+
+  void* data = const_cast<void*>(pixel_refs->data());
+  if (!data) {
+    pixel_refs->unref();
+    return;
+  }
+
+  SkPixelRef** refs = reinterpret_cast<SkPixelRef**>(data);
+  for (int i = 0; i < pixel_refs->size() / sizeof(SkPixelRef*); ++i) {
+    if (*refs && (*refs)->getURI() && strncmp(
+        (*refs)->getURI(), labelLazyDecoded, sizeof(labelLazyDecoded))) {
+      result.push_back(*refs);
+    }
+    refs++;
+  }
+  pixel_refs->unref();
+}
+
 }  // namespace cc