Bug 1475325 - 2. Add tests for hiding selection action in different cases; r=jchen

Add some tests for hiding selection action during navigation, blurring,
or clearing delegate.

mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/SelectionActionDelegateTest.kt

@@ -8,6 +8,7 @@ import org.mozilla.geckoview.GeckoResponse
 import org.mozilla.geckoview.GeckoSession
 import org.mozilla.geckoview.GeckoSession.SelectionActionDelegate.*
 import org.mozilla.geckoview.test.rule.GeckoSessionTestRule.AssertCalled
+import org.mozilla.geckoview.test.rule.GeckoSessionTestRule.NullDelegate
 import org.mozilla.geckoview.test.rule.GeckoSessionTestRule.WithDevToolsAPI
 import org.mozilla.geckoview.test.rule.GeckoSessionTestRule.WithDisplay
 import org.mozilla.geckoview.test.util.Callbacks
@@ -158,6 +159,31 @@ class SelectionActionDelegateTest : BaseSessionTest() {
                  hasSelectionAt(selectedContent.initialContent.length))
     }
 
+    @Test fun pagehide() {
+        // Navigating to another page should hide selection action.
+        testThat(selectedContent, { mainSession.loadTestPath(HELLO_HTML_PATH) }, clearsSelection())
+    }
+
+    @Test fun deactivate() {
+        // Blurring the window should hide selection action.
+        testThat(selectedContent, { mainSession.setFocused(false) }, clearsSelection())
+        mainSession.setFocused(true)
+    }
+
+    @NullDelegate(GeckoSession.SelectionActionDelegate::class)
+    @Test fun clearDelegate() {
+        var counter = 0
+        mainSession.selectionActionDelegate = object : Callbacks.SelectionActionDelegate {
+            override fun onHideAction(session: GeckoSession, reason: Int) {
+                counter++
+            }
+        }
+
+        mainSession.selectionActionDelegate = null
+        assertThat("Hide action should be called when clearing delegate",
+                   counter, equalTo(1))
+    }
+
 
     /** Interface that defines behavior for a particular type of content */
     private interface SelectedContent {