cc: Reduce picture cloning by creating at most one clone per raster thread.

This adds raster sequences to the TileManager. Raster tasks posted to
the same sequence are guaranteed to run in sequential order, which means
only one picture clone per sequence is required. We use the same number
of raster sequences as raster threads.

BUG=155209
TEST=manual


Review URL: https://chromiumcodereview.appspot.com/11419262

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@171267 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 10 insertions, 0 deletions

diff --git a/cc/picture_pile_impl.h b/cc/picture_pile_impl.h
index 93ac072..b041635 100644
--- a/cc/picture_pile_impl.h
+++ b/cc/picture_pile_impl.h
@@ -5,8 +5,11 @@
 #ifndef CC_PICTURE_PILE_IMPL_H_
 #define CC_PICTURE_PILE_IMPL_H_
 
+#include <map>
+
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
+#include "base/threading/thread.h"
 #include "cc/cc_export.h"
 #include "cc/picture.h"
 #include "cc/picture_pile.h"
@@ -20,6 +23,9 @@ class CC_EXPORT PicturePileImpl : public base::RefCounted<PicturePileImpl> {
 public:
   static scoped_refptr<PicturePileImpl> Create();
 
+  // Get paint-safe version of this picture for a specific thread.
+  PicturePileImpl* GetCloneForDrawingOnThread(base::Thread*);
+
   // Clone a paint-safe version of this picture.
   scoped_refptr<PicturePileImpl> CloneForDrawing() const;
 
@@ -40,6 +46,10 @@ private:
 
   PicturePile::Pile pile_;
 
+  typedef std::map<base::PlatformThreadId, scoped_refptr<PicturePileImpl> >
+      CloneMap;
+  CloneMap clones_;
+
   friend class base::RefCounted<PicturePileImpl>;
   DISALLOW_COPY_AND_ASSIGN(PicturePileImpl);
 };