EDK: Add implementation of data pipe producer write threshold stuff.

mojo/public/c/system/tests/core_unittest.cc

Index: mojo/public/c/system/tests/core_unittest.cc
diff --git a/mojo/public/c/system/tests/core_unittest.cc b/mojo/public/c/system/tests/core_unittest.cc
index 0ad52ad8cfcca67413c11d97925d2e3381559df3..071a902ed0fa7854da5f2e4366cdda2e69ca63b0 100644
--- a/mojo/public/c/system/tests/core_unittest.cc
+++ b/mojo/public/c/system/tests/core_unittest.cc
@@ -230,8 +230,10 @@ TEST(CoreTest, MAYBE_BasicDataPipe) {
   // The producer |hp| should be writable.
   EXPECT_EQ(MOJO_RESULT_OK,
             MojoWait(hp, MOJO_HANDLE_SIGNAL_WRITABLE, 0, &state));
-  EXPECT_EQ(MOJO_HANDLE_SIGNAL_WRITABLE, state.satisfied_signals);
-  EXPECT_EQ(MOJO_HANDLE_SIGNAL_WRITABLE | MOJO_HANDLE_SIGNAL_PEER_CLOSED,
+  EXPECT_EQ(MOJO_HANDLE_SIGNAL_WRITABLE | MOJO_HANDLE_SIGNAL_WRITE_THRESHOLD,
+            state.satisfied_signals);
+  EXPECT_EQ(MOJO_HANDLE_SIGNAL_WRITABLE | MOJO_HANDLE_SIGNAL_PEER_CLOSED |
+                MOJO_HANDLE_SIGNAL_WRITE_THRESHOLD,
             state.satisfiable_signals);
 
   // Try to read from |hc|.
@@ -315,12 +317,15 @@ TEST(CoreTest, MAYBE_BasicDataPipe) {
   // the producer never-writable?
 }
 
+// TODO(vtl): Once thunks are in: TEST(CoreTest, DataPipeWriteThreshold) { ... }
+
 TEST(CoreTest, DataPipeReadThreshold) {
   MojoHandle hp = MOJO_HANDLE_INVALID;
   MojoHandle hc = MOJO_HANDLE_INVALID;
   EXPECT_EQ(MOJO_RESULT_OK, MojoCreateDataPipe(nullptr, &hp, &hc));
   EXPECT_NE(hp, MOJO_HANDLE_INVALID);
   EXPECT_NE(hc, MOJO_HANDLE_INVALID);
+  EXPECT_NE(hc, hp);
 
   MojoDataPipeConsumerOptions copts;
   static const uint32_t kCoptsSize = static_cast<uint32_t>(sizeof(copts));