Bug 1246477 - Fix carets not updated by scroll events in LongTapState. r=roc

This is a regression by "Bug 1121468 - Go to NoActionState after
receiving release on LongTapState."

When receiving a scroll event in LongTapState, i.e. apz starts, we
should call OnScrollStart() and move to the ScrollState.

--HG--
extra : commitid : GsQNnTtqhzh
extra : rebase_source : 0a6ad44a4bf97ed15b374094929df5409deeba41

layout/base/AccessibleCaretEventHub.cpp

@@ -339,6 +339,12 @@ public:
     return nsEventStatus_eIgnore;
   }
 
+  virtual void OnScrollStart(AccessibleCaretEventHub* aContext) override
+  {
+    aContext->mManager->OnScrollStart();
+    aContext->SetState(aContext->ScrollState());
+  }
+
   virtual void OnReflow(AccessibleCaretEventHub* aContext) override
   {
     aContext->mManager->OnReflow();

layout/base/doc/AccessibleCaretEventHubStates.dot

@@ -1,6 +1,10 @@
 // Steps to generate AccessibleCaretEventHubStates.png
 // 1. Install Graphviz
 // 2. dot -T png -o AccessibleCaretEventHubStates.png AccessibleCaretEventHubStates.dot
+//
+// Note: If the edge has 'constraint=false', it is not used in ranking the
+// nodes. http://www.graphviz.org/doc/info/attrs.html#d:constraint
+
 digraph event_hub_states {
   node [style=filled];
   edge [color="gray30", fontcolor="gray20", fontsize=12]
@@ -25,6 +29,7 @@ digraph event_hub_states {
 
   LongTap [color="#E8C516"]
   LongTap -> NoAction [label="Release"];
+  LongTap -> Scroll [label="Scroll start", constraint=false];
 
   Scroll [color="#FF9022"]
   Scroll -> PostScroll [label="Scroll end"];

layout/base/gtest/TestAccessibleCaretEventHub.cpp

@@ -447,6 +447,7 @@ AccessibleCaretEventHubTester::TestLongTapWithSelectWordSuccessful(
   PressEventCreator aPressEventCreator,
   ReleaseEventCreator aReleaseEventCreator)
 {
+  MockFunction<void(::std::string aCheckPointName)> check;
   {
     InSequence dummy;
 
@@ -455,8 +456,20 @@ AccessibleCaretEventHubTester::TestLongTapWithSelectWordSuccessful(
 
     EXPECT_CALL(*mHub->GetMockAccessibleCaretManager(), SelectWordOrShortcut(_))
       .WillOnce(Return(NS_OK));
+
+    EXPECT_CALL(check, Call("longtap with scrolling"));
+
+    EXPECT_CALL(*mHub->GetMockAccessibleCaretManager(), PressCaret(_))
+      .WillOnce(Return(NS_ERROR_FAILURE));
+
+    EXPECT_CALL(*mHub->GetMockAccessibleCaretManager(), SelectWordOrShortcut(_))
+      .WillOnce(Return(NS_OK));
+
+    EXPECT_CALL(*mHub->GetMockAccessibleCaretManager(), OnScrollStart());
+    EXPECT_CALL(*mHub->GetMockAccessibleCaretManager(), OnScrollEnd());
   }
 
+  // Test long tap without scrolling.
   HandleEventAndCheckState(aPressEventCreator(0, 0),
                            MockAccessibleCaretEventHub::PressNoCaretState(),
                            nsEventStatus_eIgnore);
@@ -468,6 +481,36 @@ AccessibleCaretEventHubTester::TestLongTapWithSelectWordSuccessful(
   HandleEventAndCheckState(aReleaseEventCreator(0, 0),
                            MockAccessibleCaretEventHub::NoActionState(),
                            nsEventStatus_eIgnore);
+
+  // On Fennec, after long tap, the script might scroll and zoom the input field
+  // to the center of the screen to make typing easier before the user lifts the
+  // finger.
+  check.Call("longtap with scrolling");
+
+  HandleEventAndCheckState(aPressEventCreator(1, 1),
+                           MockAccessibleCaretEventHub::PressNoCaretState(),
+                           nsEventStatus_eIgnore);
+
+  HandleEventAndCheckState(CreateLongTapEvent(1, 1),
+                           MockAccessibleCaretEventHub::LongTapState(),
+                           nsEventStatus_eConsumeNoDefault);
+
+  mHub->AsyncPanZoomStarted();
+  EXPECT_EQ(mHub->GetState(), MockAccessibleCaretEventHub::ScrollState());
+
+  mHub->ScrollPositionChanged();
+  EXPECT_EQ(mHub->GetState(), MockAccessibleCaretEventHub::ScrollState());
+
+  mHub->AsyncPanZoomStopped();
+  EXPECT_EQ(mHub->GetState(), MockAccessibleCaretEventHub::PostScrollState());
+
+  // Simulate scroll end fired by timer.
+  MockAccessibleCaretEventHub::FireScrollEnd(nullptr, mHub);
+  EXPECT_EQ(mHub->GetState(), MockAccessibleCaretEventHub::NoActionState());
+
+  HandleEventAndCheckState(aReleaseEventCreator(1, 1),
+                           MockAccessibleCaretEventHub::NoActionState(),
+                           nsEventStatus_eIgnore);
 }
 
 TEST_F(AccessibleCaretEventHubTester, TestMouseLongTapWithSelectWordFailed)