wpt: screen enumeration: test to verify screen id

Test to verify screen id.
adding 3 displays to display vector.
getScreens() should return 3 screens with ids 0,1,2.
removing middle display from display vector.
getScreens() should return 2 screens with ids 0,1.
removing last display from display vector.
getScreens() should return 1 screen with id 0.

Bug: 1075656
Change-Id: Ib671b760353766d21330b95833b983c9b5e4737f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2238112Reviewed-by: Michael Wasserman <msw@chromium.org>
Commit-Queue: Arnaud Mandy <arnaud.mandy@intel.com>
Cr-Commit-Position: refs/heads/master@{#779689}

third_party/blink/web_tests/external/wpt/resources/chromium/mock-screenenumeration.js

@@ -33,6 +33,13 @@ var ScreenEnumerationTest = (() => {
       this.displays_.push(display);
     }
 
+    removeDisplay(id) {
+      for (var i = 0; i < this.displays_.length; i++) {
+        if (this.displays_[i].id === id)
+          this.displays_.splice(i,1);
+      }
+    }
+
     async getDisplays() {
       return Promise.resolve({
         displays: this.displays_,

third_party/blink/web_tests/external/wpt/screen_enumeration/README.md

@@ -16,6 +16,7 @@ The `ScreenEnumerationTest` interface is defined as:
     setId(internalId, primaryId); // Set primary screen and internal screen IDs.
     setSuccess(success); // Set boolean to validate getDisplays() returned values.
     addDisplay(display); // Push display to the display vector.
+    removeDisplay(id); // Remove display from the display vector.
     async getDisplays(); // Interceptor of getDisplays (screen_enumeration.mojom).
   };
 ```

third_party/blink/web_tests/external/wpt/screen_enumeration/getScreens.values.https.html

@@ -23,7 +23,7 @@ screen_enumeration_test(async (t, mockScreenEnum) => {
   // Grant window-placement permissions for testdriver.
   await test_driver.set_permission({name: "window-placement"}, "granted");
 
-  // This call is calling GetDisplays, which should fall in interceptor.
+  // This returns the mocked displays via MockScreenEnumeration implementation.
   const screens = await self.getScreens();
 
   assert_equals(screens.length, 1);
@@ -41,4 +41,52 @@ screen_enumeration_test(async (t, mockScreenEnum) => {
   assert_equals(screens[0].scaleFactor, 1.0);
   assert_equals(screens[0].id, "0");
 }, "getScreens() returns a single mocked screen");
+
+screen_enumeration_test(async (t, mockScreenEnum) => {
+  let display1 = makeDisplay(10,
+                             {x: 0, y: 10, width: 1200, height: 800},
+                             {x: 20, y: 30, width: 1000, height: 600},
+                             1.0);
+
+  let display2 = makeDisplay(11,
+                             {x: 0, y: 10, width: 1200, height: 800},
+                             {x: 20, y: 30, width: 1000, height: 600},
+                             1.0);
+
+  let display3 = makeDisplay(12,
+                             {x: 0, y: 10, width: 1200, height: 800},
+                             {x: 20, y: 30, width: 1000, height: 600},
+                             1.0);
+
+  mockScreenEnum.addDisplay(display1);
+  mockScreenEnum.addDisplay(display2);
+  mockScreenEnum.addDisplay(display3);
+  mockScreenEnum.setIds(mockScreenEnum.displays_[0].id, mockScreenEnum.displays_[0].id);
+  mockScreenEnum.setSuccess(true);
+
+  // Grant window-placement permissions for testdriver.
+  await test_driver.set_permission({name: "window-placement"}, "granted");
+
+  // This returns the mocked displays via MockScreenEnumeration implementation.
+  let screens = await self.getScreens();
+
+  assert_equals(screens.length, 3);
+  assert_equals(screens[0].id, "0");
+  assert_equals(screens[1].id, "1");
+  assert_equals(screens[2].id, "2");
+
+  mockScreenEnum.removeDisplay(display2.id);
+
+  screens = await self.getScreens();
+  assert_equals(screens.length, 2);
+  assert_equals(screens[0].id, "0");
+  assert_equals(screens[1].id, "1");
+
+  mockScreenEnum.removeDisplay(display1.id);
+
+  screens = await self.getScreens();
+  assert_equals(screens.length, 1);
+  assert_equals(screens[0].id, "0");
+}, "getScreens() supports multiple mocked screens");
+
 </script>