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

cc/base/region_unittest.cc

Index: cc/base/region_unittest.cc
diff --git a/cc/base/region_unittest.cc b/cc/base/region_unittest.cc
index c9a218d692a7b95f68f8c6fb693ae9c2563b86bc..99a17b2f877aaf48b7e4a20c6329767cd011e50c 100644
--- a/cc/base/region_unittest.cc
+++ b/cc/base/region_unittest.cc
@@ -4,6 +4,7 @@
 
 #include "cc/base/region.h"
 
+#include "cc/proto/region.pb.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace cc {
@@ -450,5 +451,14 @@ TEST(RegionSwap, Swap) {
   EXPECT_EQ(r2.ToString(), r3.ToString());
 }
 
+TEST(RegionTest, ProtoConversion) {
+  Region region1(gfx::Rect(14, 15, 16, 17));
+  proto::Region proto;
+  region1.ToProtobuf(&proto);
+  Region region2;
+  region2.FromProtobuf(proto);
+  EXPECT_EQ(region1, region2);
+}
+
 }  // namespace
 }  // namespace cc