Blimp: Add BlobChannel Helium messages and delegate impls.

blimp/common/logging_unittest.cc

Index: blimp/common/logging_unittest.cc
diff --git a/blimp/common/logging_unittest.cc b/blimp/common/logging_unittest.cc
index 58b4b742935aaa3ab14f211c1e5891d6d25e367a..6d2edbd4be950de464de2ea39941380cf1729615 100644
--- a/blimp/common/logging_unittest.cc
+++ b/blimp/common/logging_unittest.cc
@@ -7,8 +7,10 @@
 
 #include "base/at_exit.h"
 #include "base/strings/stringprintf.h"
+#include "blimp/common/create_blimp_message.h"
 #include "blimp/common/logging.h"
 #include "blimp/common/proto/blimp_message.pb.h"
+#include "blimp/common/proto/blob_channel.pb.h"
 #include "blimp/net/test_common.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -220,6 +222,18 @@ TEST_F(LoggingTest, RenderWidget) {
                   deleted_msg);
 }
 
+TEST_F(LoggingTest, BlobChannel) {
+  BlobChannelMessage* blob_message = nullptr;
+  std::unique_ptr<BlimpMessage> blimp_message =
+      CreateBlimpMessage(&blob_message);
+  blob_message->mutable_transfer_blob()->set_blob_id("AAA");
+  blob_message->mutable_transfer_blob()->set_payload("123");
+
+  VerifyLogOutput(
+      "type=BLOB_CHANNEL subtype=TRANSFER_BLOB id=\"414141\" payload_size=3",
+      *blimp_message);
+}
+
 TEST_F(LoggingTest, Settings) {
   BlimpMessage message;
   message.mutable_settings()