Bug 1195722 - On desktop, allow the context menu to pop up concurrently with text selection. r=tylin

On desktop, the context menu is shown when the user lifts their finger after
a long press, but only if the eMouseLongTap event is not cancelled. So by
not cancelling it, we allow both the text selection and the context menu.

On Android, the context menu takes priority over text selection, so this
has no effect (i.e. if the context menu is shown, then the AccessibleCaret
code never even gets the eMouseLongTap event). Also on Android nothing
else relies on the cancellation of the eMouseLongTap event, so this change
is a no-op.

MozReview-Commit-ID: peFzB2afha

layout/base/AccessibleCaretEventHub.cpp

@@ -322,13 +322,12 @@ public:
   virtual nsEventStatus OnLongTap(AccessibleCaretEventHub* aContext,
                                   const nsPoint& aPoint) override
   {
-    nsEventStatus rv = nsEventStatus_eIgnore;
-
-    if (NS_SUCCEEDED(aContext->mManager->SelectWordOrShortcut(aPoint))) {
-      rv = nsEventStatus_eConsumeNoDefault;
-    }
-
-    return rv;
+    // In general text selection is lower-priority than the context menu. If
+    // we consume this long-press event, then it prevents the context menu from
+    // showing up on desktop Firefox (because that happens on long-tap-up, if
+    // the long-tap was not cancelled). So we return eIgnore instead.
+    aContext->mManager->SelectWordOrShortcut(aPoint);
+    return nsEventStatus_eIgnore;
   }
 
   virtual nsEventStatus OnRelease(AccessibleCaretEventHub* aContext) override

layout/base/gtest/TestAccessibleCaretEventHub.cpp

@@ -550,7 +550,7 @@ AccessibleCaretEventHubTester::TestLongTapWithSelectWordSuccessful(
 
   HandleEventAndCheckState(CreateLongTapEvent(0, 0),
                            MockAccessibleCaretEventHub::LongTapState(),
-                           nsEventStatus_eConsumeNoDefault);
+                           nsEventStatus_eIgnore);
 
   HandleEventAndCheckState(aReleaseEventCreator(0, 0),
                            MockAccessibleCaretEventHub::NoActionState(),
@@ -567,7 +567,7 @@ AccessibleCaretEventHubTester::TestLongTapWithSelectWordSuccessful(
 
   HandleEventAndCheckState(CreateLongTapEvent(1, 1),
                            MockAccessibleCaretEventHub::LongTapState(),
-                           nsEventStatus_eConsumeNoDefault);
+                           nsEventStatus_eIgnore);
 
   mHub->AsyncPanZoomStarted();
   EXPECT_EQ(mHub->GetState(), MockAccessibleCaretEventHub::ScrollState());