Add glue between the client and engine for Blimp

- Add BlimpMessageProcessors to handle RENDER_WIDGET, INPUT, and
  COMPOSITOR message types to/from the client and engine.
- Tie the message processors into BlimpCompositor on the client and
  BlimpEngineSession on the server.
- Update BlimpView and BlimpCompositor to fix how we handle output
  surfaces and how we shut down and build the LayerTreeHost based on
  incoming RENDER_WIDGET and COMPOSITOR messages.

BUG=550693

Review URL: https://codereview.chromium.org/1450423002

Cr-Commit-Position: refs/heads/master@{#362299}

7 files changed, 62 insertions, 20 deletions

diff --git a/blimp/common/proto/BUILD.gn b/blimp/common/proto/BUILD.gn
index 5ca8283..fa564eb 100644
--- a/blimp/common/proto/BUILD.gn
+++ b/blimp/common/proto/BUILD.gn
@@ -26,11 +26,12 @@ proto_library("proto_internal") {
 
   sources = [
     "blimp_message.proto",
-    "common.proto",
     "compositor.proto",
     "control.proto",
     "input.proto",
     "navigation.proto",
+    "render_widget.proto",
+    "size.proto",
   ]
 
   cc_generator_options = "dllexport_decl=BLIMP_PROTO_EXPORT:"
diff --git a/blimp/common/proto/blimp_message.proto b/blimp/common/proto/blimp_message.proto
index 9b11684..505e0f4 100644
--- a/blimp/common/proto/blimp_message.proto
+++ b/blimp/common/proto/blimp_message.proto
@@ -18,7 +18,6 @@
 // * Features are applied to unidirectional channels. Client->server and
 //   server->client channels for a component should be broken out as distinct
 //   features, even if they are conceptually similar.
-// * Shared proto types are contained in 'common.proto'.
 
 syntax = "proto2";
 
@@ -28,16 +27,18 @@ import "control.proto";
 import "compositor.proto";
 import "input.proto";
 import "navigation.proto";
+import "render_widget.proto";
 
 package blimp;
 
 message BlimpMessage {
   enum Type {
     UNKNOWN = 0;
-    COMPOSITOR = 1;
-    INPUT = 2;
-    CONTROL = 3;
-    NAVIGATION = 4;
+    CONTROL = 1;
+    NAVIGATION = 2;
+    RENDER_WIDGET = 3;
+    INPUT = 4;
+    COMPOSITOR = 5;
   }
   // Identifies the feature type of this message.
   // The feature-specific contents are contained in optional fields of the same
@@ -58,9 +59,10 @@ message BlimpMessage {
   // Feature-specific messages follow.
   // Only one of these fields may be set per BlimpMessage.
   // TODO(kmarshall): use a 'oneof' union when it's supported in Chromium.
-  optional CompositorMessage compositor = 1000;
-  optional InputMessage input = 1001;
-  optional ControlMessage control = 1002;
-  optional NavigationMessage navigation = 1003;
+  optional ControlMessage control = 1000;
+  optional NavigationMessage navigation = 1001;
+  optional RenderWidgetMessage render_widget = 1002;
+  optional InputMessage input = 1003;
+  optional CompositorMessage compositor = 1004;
 }
 
diff --git a/blimp/common/proto/compositor.proto b/blimp/common/proto/compositor.proto
index bd5f826..a015c24 100644
--- a/blimp/common/proto/compositor.proto
+++ b/blimp/common/proto/compositor.proto
@@ -4,8 +4,6 @@
 //
 // Message definitions for the compositor subprotocol.
 
-// TODO(nyquist): Import cc proto files.
-
 syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
@@ -13,6 +11,11 @@ option optimize_for = LITE_RUNTIME;
 package blimp;
 
 message CompositorMessage {
-  // TODO(nyquist): Include the cc proto message here.
+  // An ID that corresponds to RenderWidgetMessage.render_widget_id.
+  optional uint32 render_widget_id = 1;
+
+  // This represents a serialized CompositorMessage in
+  // cc/proto/compositor_message.proto.
+  optional bytes payload = 2;
 }
 
diff --git a/blimp/common/proto/control.proto b/blimp/common/proto/control.proto
index bcb9aaa..1a909b6 100644
--- a/blimp/common/proto/control.proto
+++ b/blimp/common/proto/control.proto
@@ -8,6 +8,10 @@ syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
 
+import "size.proto";
+
+package blimp;
+
 message ControlMessage {
   enum Type {
     UNKNOWN = 0;
@@ -15,6 +19,14 @@ message ControlMessage {
     // Client <=> Server types.
     CREATE_TAB = 1;
     CLOSE_TAB = 2;
+
+    // Client => Server types.
+    SIZE = 3;
   }
+
   optional Type type = 1;
+
+  // Feature-specific messages follow.
+  // Only one of these fields may be set per ControlMessage.
+  optional SizeMessage resize = 1000;
 }
diff --git a/blimp/common/proto/input.proto b/blimp/common/proto/input.proto
index fa6fe62..7b9a404 100644
--- a/blimp/common/proto/input.proto
+++ b/blimp/common/proto/input.proto
@@ -11,8 +11,6 @@ syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
 
-import "common.proto";
-
 package blimp;
 
 message GestureCommon {
@@ -78,6 +76,9 @@ message InputMessage {
 
   optional Type type = 1;
 
+  // An ID that corresponds to RenderWidgetMessage.render_widget_id.
+  optional uint32 render_widget_id = 10;
+
   // Seconds since client platform start (boot) with millisecond resolution.
   // On Android, this is based off of the client's SystemClock#uptimeMillis().
   optional double timestamp_seconds = 2;
diff --git a/blimp/common/proto/render_widget.proto b/blimp/common/proto/render_widget.proto
new file mode 100644
index 0000000..480371b
--- /dev/null
+++ b/blimp/common/proto/render_widget.proto
@@ -0,0 +1,23 @@
+// 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.
+//
+
+syntax = "proto2";
+
+option optimize_for = LITE_RUNTIME;
+
+package blimp;
+
+message RenderWidgetMessage {
+  enum Type {
+    // TODO(dtrainor): Leaving this a bit open in case we need to send other
+    // types of RenderWidget messages (like shutdown).
+
+    // Engine => Client types.
+    INITIALIZE = 1;
+  }
+
+  optional Type type = 1;
+  optional uint32 render_widget_id = 2;
+}
\ No newline at end of file
diff --git a/blimp/common/proto/common.proto b/blimp/common/proto/size.proto
index 578c02b..f6ba801 100644
--- a/blimp/common/proto/common.proto
+++ b/blimp/common/proto/size.proto
@@ -1,8 +1,6 @@
 // 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.
-//
-// Common message types for sharing across Blimp subprotocols.
 
 syntax = "proto2";
 
@@ -10,8 +8,10 @@ option optimize_for = LITE_RUNTIME;
 
 package blimp;
 
-message CoordinatePair {
-  optional sint32 x = 1;
-  optional sint32 y = 2;
+// Contains display information that represents resize events coming from the
+// client device.
+message SizeMessage {
+  optional uint64 width = 1;
+  optional uint64 height = 2;
 }