[Blimp] Adds Blimp EngineSession and ClientSession skeleton.

BlimpClientSessionManager (to be added) authenticates and creates client sessions. Once a client session is authenticated, it is given to the engine session. There is at most one active client session attached to the engine session.

The engine session manages a list of web contents.

Review URL: https://codereview.chromium.org/1403083002

Cr-Commit-Position: refs/heads/master@{#354388}

5 files changed, 32 insertions, 80 deletions

diff --git a/blimp/common/proto/BUILD.gn b/blimp/common/proto/BUILD.gn
index db60779..ecaa29c 100644
--- a/blimp/common/proto/BUILD.gn
+++ b/blimp/common/proto/BUILD.gn
@@ -14,10 +14,9 @@ group("proto") {
 proto_library("proto_lib") {
   sources = [
     "blimp_message.proto",
-    "client_control.proto",
     "common.proto",
     "compositor.proto",
+    "control.proto",
     "input.proto",
-    "server_control.proto",
   ]
 }
diff --git a/blimp/common/proto/blimp_message.proto b/blimp/common/proto/blimp_message.proto
index 9472f9e..553119d 100644
--- a/blimp/common/proto/blimp_message.proto
+++ b/blimp/common/proto/blimp_message.proto
@@ -24,10 +24,9 @@ syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
 
-import "client_control.proto";
+import "control.proto";
 import "compositor.proto";
 import "input.proto";
-import "server_control.proto";
 
 package blimp;
 
@@ -35,8 +34,7 @@ message BlimpMessage {
   enum Type {
     COMPOSITOR = 0;
     INPUT = 1;
-    CLIENT_CONTROL = 2;
-    SERVER_CONTROL = 3;
+    CONTROL = 2;
   }
   // Identifies the feature type of this message.
   // The feature-specific contents are contained in optional fields of the same
@@ -59,7 +57,6 @@ message BlimpMessage {
   // TODO(kmarshall): use a 'oneof' union when it's supported in Chromium.
   optional CompositorMessage compositor = 1000;
   optional InputMessage input = 1001;
-  optional ClientControlMessage client_control = 1002;
-  optional ServerControlMessage server_control = 1003;
+  optional ControlMessage control = 1002;
 }
 
diff --git a/blimp/common/proto/client_control.proto b/blimp/common/proto/client_control.proto
deleted file mode 100644
index 6d9f605..0000000
--- a/blimp/common/proto/client_control.proto
+++ /dev/null
@@ -1,29 +0,0 @@
-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-//
-// Message definitions for client-originating browser control messages.
-//
-// Current definitions are just placeholders and are NOT final.
-// Feel free to modify this interface as necessary during feature work.
-
-syntax = "proto2";
-
-option optimize_for = LITE_RUNTIME;
-
-message NavigateArgs {
-  optional string url = 1;
-}
-
-message ClientControlMessage {
-  enum Type {
-    NAVIGATE = 1;
-    STOP = 2;
-    RELOAD = 3;
-    BACK = 4;
-    FORWARD = 5;
-  }
-  optional Type type = 1;
-
-  optional NavigateArgs navigate = 1000;
-}
diff --git a/blimp/common/proto/control.proto b/blimp/common/proto/control.proto
new file mode 100644
index 0000000..fdc1c89
--- /dev/null
+++ b/blimp/common/proto/control.proto
@@ -0,0 +1,28 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// Message definitions for browser control messages.
+
+syntax = "proto2";
+
+option optimize_for = LITE_RUNTIME;
+
+message LoadUrlMessage {
+  optional string url = 1;
+}
+
+message ControlMessage {
+  enum Type {
+    // Client <=> Server types.
+    CREATE_TAB = 1;
+    CLOSE_TAB = 2;
+    LOAD_URL = 3;
+
+    // Server => Client types.
+    // Client => Server types.
+  }
+  optional Type type = 1;
+
+  optional LoadUrlMessage load_url = 1000;
+}
diff --git a/blimp/common/proto/server_control.proto b/blimp/common/proto/server_control.proto
deleted file mode 100644
index f1cf976..0000000
--- a/blimp/common/proto/server_control.proto
+++ /dev/null
@@ -1,43 +0,0 @@
-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-//
-// Message definitions for server-originating browser control messages.
-//
-// Current definitions are just placeholders and are NOT final.
-// Feel free to modify this interface as necessary during feature work.
-
-syntax = "proto2";
-
-option optimize_for = LITE_RUNTIME;
-
-message StatusArgs {
-  optional string url = 1;
-  optional int32 loading_progress = 2;
-  // Add error code, error message, status strings, etc.
-}
-
-message ResetSessionArgs {
-}
-
-message ErrorArgs {
-  enum ErrorCode {
-    UNKNOWN = 1;
-    UNRESPONSIVE = 2;
-    SERVER_ERROR = 3;
-  }
-
-  optional ErrorCode error_code = 1;
-  optional int32 server_error_code = 2;
-}
-
-message ServerControlMessage {
-  enum Type {
-    ERROR = 1;
-    STATUS = 2;
-  }
-  optional Type type = 1;
-
-  optional ErrorArgs error = 1000;
-  optional StatusArgs status = 1001;
-}