Add support for converting cc::Region to and from protobuf.

cc/base/region.cc

Index: cc/base/region.cc
diff --git a/cc/base/region.cc b/cc/base/region.cc
index c048c89e5710ba0412910008c9eabb2fdaa37abc..0a2f0c2b62447c56791ba372d7f2def64ed1a823 100644
--- a/cc/base/region.cc
+++ b/cc/base/region.cc
@@ -7,6 +7,7 @@
 #include "base/trace_event/trace_event_argument.h"
 #include "base/values.h"
 #include "cc/base/simple_enclosed_region.h"
+#include "cc/proto/region.pb.h"
 
 namespace cc {
 
@@ -140,6 +141,25 @@ void Region::AsValueInto(base::trace_event::TracedValue* result) const {
   }
 }
 
+void Region::ToProtobuf(proto::Region* proto) const {
+  size_t region_size = skregion_.writeToMemory(nullptr);
+  if (region_size > 0) {
+    scoped_ptr<uint8_t> buffer(new uint8_t[region_size]);
+    skregion_.writeToMemory(buffer.get());
+    proto->set_skregion(buffer.get(), region_size);

[David Trainor- moved to gerrit, 2015/11/20 21:46:50]

base::checked_cast<int>?  IIRC set_skregion() will take an int for the size.

+  }
+}
+
+void Region::FromProtobuf(const proto::Region& proto) {
+  SkRegion region;
+  if (proto.has_skregion()) {
+    size_t bytes_read =
+        region.readFromMemory(proto.skregion().data(), proto.skregion().size());
+    DCHECK_EQ(proto.skregion().size(), bytes_read);
+  }
+  skregion_ = region;
+}
+
 Region::Iterator::Iterator() {
 }