Add enum for TabDragController mode and replace various state flags with it.

Also changes what happens when the drag ends during a nested move loop.  It
now exits the move loop (which triggers a drag end) instead of immediately
ending the drag.

This is the first step in a larger refactoring for TabDragController:
go/tabdragcontroller-untangling

Change-Id: I6cabc5237a604320c934bb8b5d4bbc9ff6d231f0
Reviewed-on: https://chromium-review.googlesource.com/c/1285085
Commit-Queue: Taylor Bergquist <tbergquist@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611352}

chrome/browser/ui/views/tabs/tab_drag_controller.h

@@ -114,18 +114,20 @@ class TabDragController : public views::WidgetObserver,
   EventSource event_source() const { return event_source_; }
 
   // See description above fields for details on these.
-  bool active() const { return active_; }
+  bool active() const { return current_state_ != DragState::kStopped; }
   const TabStrip* attached_tabstrip() const { return attached_tabstrip_; }
 
   // Returns true if a drag started.
-  bool started_drag() const { return started_drag_; }
+  bool started_drag() const { return current_state_ != DragState::kNotStarted; }
 
   // Returns true if mutating the TabStripModel.
   bool is_mutating() const { return is_mutating_; }
 
   // Returns true if we've detached from a tabstrip and are running a nested
   // move message loop.
-  bool is_dragging_window() const { return is_dragging_window_; }
+  bool is_dragging_window() const {
+    return current_state_ == DragState::kDraggingWindow;
+  }
 
   // Returns true if currently dragging a tab with |contents|.
   bool IsDraggingTab(content::WebContents* contents);
@@ -143,6 +145,24 @@ class TabDragController : public views::WidgetObserver,
   static const int kMovedMouseLeft  = 1 << 0;
   static const int kMovedMouseRight = 1 << 1;
 
+  enum class DragState {
+    // The drag has not yet started; the user has not dragged far enough to
+    // begin a session.
+    kNotStarted,
+    // The session is dragging a set of tabs within |attached_tabstrip_|.
+    kDraggingTabs,
+    // The session is dragging a window; |attached_tabstrip_| is that window's
+    // tabstrip.
+    kDraggingWindow,
+    // The session is waiting for the nested move loop to exit to transition
+    // to kDraggingTabs.  Not used on all platforms.
+    kWaitingToDragTabs,
+    // The session is waiting for the nested move loop to exit to end the drag.
+    kWaitingToStop,
+    // The drag session has completed or been canceled.
+    kStopped
+  };
+
   enum class Liveness {
     ALIVE,
     DELETED,
@@ -166,15 +186,6 @@ class TabDragController : public views::WidgetObserver,
     DONT_RELEASE_CAPTURE,
   };
 
-  // Specifies what should happen when RunMoveLoop completes.
-  enum EndRunLoopBehavior {
-    // Indicates the drag should end.
-    END_RUN_LOOP_STOP_DRAGGING,
-
-    // Indicates the drag should continue.
-    END_RUN_LOOP_CONTINUE_DRAGGING
-  };
-
   // Enumeration of the possible positions the detached tab may detach from.
   enum DetachPosition {
     DETACH_BEFORE,
@@ -473,6 +484,8 @@ class TabDragController : public views::WidgetObserver,
   // property.
   void SetDeferredTargetTabstrip(TabStrip* deferred_target_tabstrip);
 
+  DragState current_state_;
+
   // Whether a drag to |window| should be blocked (for example, if the window
   // is showing a modal).
   bool ShouldDisallowDrag(gfx::NativeWindow window);
@@ -544,12 +557,6 @@ class TabDragController : public views::WidgetObserver,
   // StartMoveStackedTimerIfNecessary().
   base::OneShotTimer move_stacked_timer_;
 
-  // Did the mouse move enough that we started a drag?
-  bool started_drag_;
-
-  // Is the drag active?
-  bool active_;
-
   DragData drag_data_;
 
   // Index of the source tab in |drag_data_|.
@@ -591,9 +598,6 @@ class TabDragController : public views::WidgetObserver,
   // The following are needed when detaching into a browser
   // (|detach_into_browser_| is true).
 
-  // See description above getter.
-  bool is_dragging_window_;
-
   // True if |attached_tabstrip_| is in a browser specifically created for
   // the drag.
   bool is_dragging_new_browser_;
@@ -608,11 +612,6 @@ class TabDragController : public views::WidgetObserver,
   // maximized).
   bool did_restore_window_;
 
-  EndRunLoopBehavior end_run_loop_behavior_;
-
-  // If true, we're waiting for a move loop to complete.
-  bool waiting_for_run_loop_to_exit_;
-
   // The TabStrip to attach to after the move loop completes.
   TabStrip* tab_strip_to_attach_to_after_exit_;
 

chrome/browser/ui/views/tabs/tab_drag_controller_interactive_uitest.cc

@@ -246,6 +246,11 @@ void TabDragControllerTest::HandleGestureEvent(TabStrip* tab_strip,
   tab_strip->OnGestureEvent(event);
 }
 
+bool TabDragControllerTest::HasDragStarted(const TabStrip* tab_strip) const {
+  return tab_strip->drag_controller_ &&
+         tab_strip->drag_controller_->started_drag();
+}
+
 void TabDragControllerTest::SetUp() {
 #if defined(USE_AURA)
   // This needs to be disabled as it can interfere with when events are
@@ -1210,6 +1215,31 @@ IN_PROC_BROWSER_TEST_P(DetachToBrowserTabDragControllerTest,
   EXPECT_FALSE(GetIsDragged(browser()));
 }
 
+IN_PROC_BROWSER_TEST_P(DetachToBrowserTabDragControllerTest,
+                       DragDoesntStartFromClick) {
+  // Add another tab.
+  AddTabAndResetBrowser(browser());
+  TabStrip* tab_strip = GetTabStripForBrowser(browser());
+
+  // Click on the first tab, but don't move it.
+  gfx::Point tab_0_center(GetCenterInScreenCoordinates(tab_strip->tab_at(0)));
+  EXPECT_TRUE(PressInput(tab_0_center));
+
+  // A drag session should exist, but the drag should not have started.
+  EXPECT_TRUE(tab_strip->IsDragSessionActive());
+  EXPECT_TRUE(TabDragController::IsActive());
+  EXPECT_FALSE(HasDragStarted(tab_strip));
+
+  // Move the mouse enough to start the drag.  It doesn't matter whether this
+  // is enough to create a window or not.
+  EXPECT_TRUE(DragInputTo(gfx::Point(tab_0_center.x() + 20, tab_0_center.y())));
+
+  // Drag should now have started.
+  EXPECT_TRUE(HasDragStarted(tab_strip));
+
+  EXPECT_TRUE(ReleaseInput());
+}
+
 #if defined(OS_CHROMEOS)
 // TODO(sky,sad): Disabled as it fails due to resize locks with a real
 // compositor. crbug.com/331924

chrome/browser/ui/views/tabs/tab_drag_controller_interactive_uitest.h

@@ -50,6 +50,8 @@ class TabDragControllerTest : public InProcessBrowserTest {
  protected:
   void HandleGestureEvent(TabStrip* tab_strip, ui::GestureEvent* event);
 
+  bool HasDragStarted(const TabStrip* tab_strip) const;
+
   // InProcessBrowserTest:
   void SetUp() override;