[CastRunner] Allow Agent's enable-touch bindings to supercede the Runner's.

Prevents the CastRunner from clobbering the Agent's
setTouchSupportEnabled() platform API if it's already been installed.

Bug: 953796,953958
Change-Id: Ia1044a96209f04d792a8c671a8ac18eb98b2d9ce
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1728445Reviewed-by: Fabrice de Gans-Riberi <fdegans@chromium.org>
Commit-Queue: Kevin Marshall <kmarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683227}

fuchsia/runners/cast/touch_input_bindings.js

@@ -4,70 +4,73 @@
 
 'use strict';
 
-cast.__platform__.__touchInput__ = new class {
-  constructor() {
-    this.port_ = cast.__platform__.PortConnector.bind(
-        'cast.__platform__.__touchInput__');
+// Don't supercede an Agent-provided API function.
+if (!cast.__platform__.setTouchInputSupport) {
+  cast.__platform__.__touchInput__ = new class {
+    constructor() {
+      this.port_ = cast.__platform__.PortConnector.bind(
+          'cast.__platform__.__touchInput__');
 
-    this.port_.onmessage = function(message) {
-          var responseParsed = JSON.parse(message.data);
-          if (responseParsed) {
-            this.onAck(responseParsed.requestId,
-                responseParsed.displayControls);
-          }
-        }.bind(this);
-  }
-
-  // Receives an acknowledgement from the native bindings layer and relays the
-  // result to the Promise.
-  onAck(requestId, displayControls) {
-    if (!this.pendingRequests_.hasOwnProperty(requestId)) {
-      console.error('Received ack for unknown request ID: ' + requestId);
-      return;
+      this.port_.onmessage = function(message) {
+            var responseParsed = JSON.parse(message.data);
+            if (responseParsed) {
+              this.onAck(responseParsed.requestId,
+                  responseParsed.displayControls);
+            }
+          }.bind(this);
     }
 
-    var request = this.pendingRequests_[requestId];
-    delete this.pendingRequests_[requestId];
+    // Receives an acknowledgement from the native bindings layer and relays the
+    // result to the Promise.
+    onAck(requestId, displayControls) {
+      if (!this.pendingRequests_.hasOwnProperty(requestId)) {
+        console.error('Received ack for unknown request ID: ' + requestId);
+        return;
+      }
+
+      var request = this.pendingRequests_[requestId];
+      delete this.pendingRequests_[requestId];
 
-    if (displayControls === undefined) {
-      request.reject();
-    } else {
-      request.resolve({'displayControls': displayControls});
+      if (displayControls === undefined) {
+        request.reject();
+      } else {
+        request.resolve({'displayControls': displayControls});
+      }
     }
-  }
 
-  // Requests touch input support from the native bindings layer and returns a
-  // Promise with the result.
-  // If the request was successful, the Promise will be resolved with a
-  // dictionary indicating whether onscreen controls should be shown for the
-  // application.
-  // If the request was rejected, then the Promise will be rejected.
-  setTouchInputSupport(touchEnabled) {
-    return new Promise((resolve, reject) => {
-      var requestId = this.currentRequestId_++;
-      this.pendingRequests_[requestId] = {
-        'resolve': resolve,
-        'reject': reject,
-      };
-      this.port_.postMessage(JSON.stringify({
-        'requestId': requestId,
-        'touchEnabled': touchEnabled,
-      }));
-    });
-  }
+    // Requests touch input support from the native bindings layer and returns a
+    // Promise with the result.
+    // If the request was successful, the Promise will be resolved with a
+    // dictionary indicating whether onscreen controls should be shown for the
+    // application.
+    // If the request was rejected, then the Promise will be rejected.
+    setTouchInputSupport(touchEnabled) {
+      return new Promise((resolve, reject) => {
+        var requestId = this.currentRequestId_++;
+        this.pendingRequests_[requestId] = {
+          'resolve': resolve,
+          'reject': reject,
+        };
+        this.port_.postMessage(JSON.stringify({
+          'requestId': requestId,
+          'touchEnabled': touchEnabled,
+        }));
+      });
+    }
 
-  // Port for sending requests and receiving acknowledgements with the native
-  // bindings layer.
-  port_ = null;
+    // Port for sending requests and receiving acknowledgements with the native
+    // bindings layer.
+    port_ = null;
 
-  // A dictionary relating inflight request IDs to their Promise resolve/reject
-  // functions.
-  pendingRequests_ = {};
+    // A dictionary relating inflight request IDs to their Promise
+    // resolve/reject functions.
+    pendingRequests_ = {};
 
-  // Unique ID of the next request.
-  currentRequestId_ = 0;
-};
+    // Unique ID of the next request.
+    currentRequestId_ = 0;
+  };
 
-cast.__platform__.setTouchInputSupport =
-    cast.__platform__.__touchInput__.setTouchInputSupport.bind(
-        cast.__platform__.__touchInput__);
+  cast.__platform__.setTouchInputSupport =
+      cast.__platform__.__touchInput__.setTouchInputSupport.bind(
+          cast.__platform__.__touchInput__);
+}