Delay Input.dispatchKeyEvent response until after key event ack.

third_party/WebKit/Source/core/inspector/browser_protocol.json

Index: third_party/WebKit/Source/core/inspector/browser_protocol.json
diff --git a/third_party/WebKit/Source/core/inspector/browser_protocol.json b/third_party/WebKit/Source/core/inspector/browser_protocol.json
index 0e8e4d9ee34430b6f0f4c75fc9e66956f691d284..2d4b2b862a5634dbec071e570906a325d1c61cec 100644
--- a/third_party/WebKit/Source/core/inspector/browser_protocol.json
+++ b/third_party/WebKit/Source/core/inspector/browser_protocol.json
@@ -3692,6 +3692,7 @@
         "commands": [
             {
                 "name": "dispatchKeyEvent",
+                "async": true,
                 "parameters": [
                     { "name": "type", "type": "string", "enum": ["keyDown", "keyUp", "rawKeyDown", "char"], "description": "Type of the key event." },
                     { "name": "modifiers", "type": "integer", "optional": true, "description": "Bit field representing pressed modifier keys. Alt=1, Ctrl=2, Meta/Command=4, Shift=8 (default: 0)." },
@@ -3712,6 +3713,7 @@
             },
             {
                 "name": "dispatchMouseEvent",
+                "async": true,
                 "parameters": [
                     { "name": "type", "type": "string", "enum": ["mousePressed", "mouseReleased", "mouseMoved"], "description": "Type of the mouse event." },
                     { "name": "x", "type": "integer", "description": "X coordinate of the event relative to the main frame's viewport."},