Add SurfaceSequence mojom file to cc/ipc and edit corresponding GYP file

cc/surfaces/BUILD.gn

Index: cc/surfaces/BUILD.gn
diff --git a/cc/surfaces/BUILD.gn b/cc/surfaces/BUILD.gn
index 1c5ca5cc08578caf592c1fd6df8068bc48a17ba6..a420265b4a2664525084f2d840bf9f45bc1259e5 100644
--- a/cc/surfaces/BUILD.gn
+++ b/cc/surfaces/BUILD.gn
@@ -12,6 +12,16 @@ source_set("surface_id") {
   ]
 }
 
+source_set("surface_sequence") {

[Fady Samuel, 2016/06/06 18:34:30]

Do we need this? Can't you just dep on all of surfaces?

[xlai (Olivia), 2016/06/06 19:04:32]

Same rationale as above. I think it's better to isolate surface_id and
surface_sequence, because that's all I need. Adding others may again introduce a
whole bunch of other dependent targets unnecessarily.

+  sources = [
+    "surface_sequence.h",
+  ]
+
+  deps = [
+    "//base",
+  ]
+}
+
 component("surfaces") {
   output_name = "cc_surfaces"
   sources = [
@@ -40,6 +50,7 @@ component("surfaces") {
     "surface_manager.h",
     "surface_resource_holder.cc",
     "surface_resource_holder.h",
+    "surface_sequence.h",
     "surfaces_export.h",
   ]
 
@@ -47,6 +58,7 @@ component("surfaces") {
 
   public_deps = [
     ":surface_id",
+    ":surface_sequence",
   ]
   deps = [
     "//base",