Simplify view controller presentation code

Removes duplicate code related to presenting a view controller from the
FLEX window (usually triggered by a toolbar button).

This adds `-[FLEXExplorerViewController
presentOrDismissViewControllerFromToolbar:shouldDismiss:completion:]`
which also makes it easier for others to add their own toolbar buttons
to present some other kind of screen, or for FLEX itself to utilize
again in the future.

Classes/ExplorerInterface/FLEXExplorerViewController.h

@@ -17,6 +17,12 @@
 - (BOOL)shouldReceiveTouchAtWindowPoint:(CGPoint)pointInWindowCoordinates;
 - (BOOL)wantsWindowToBecomeKey;
 
+/// @brief Used to present (or dismiss) a modal view controller ("tool"), typically triggered by pressing a button in the toolbar.
+///
+/// If a tool is already presented, this method simply dismisses it and calls the completion block.
+/// If no tool is presented, @code future() @endcode is presented and the completion block is called.
+- (void)toggleToolWithViewControllerProvider:(UIViewController *(^)())future completion:(void(^)())completion;
+
 // Keyboard shortcut helpers
 
 - (void)toggleSelectTool;

Classes/ExplorerInterface/FLEXExplorerViewController.m

@@ -755,7 +755,7 @@ typedef NS_ENUM(NSUInteger, FLEXExplorerMode) {
 {
     // Note that we need to wait until the view controller is dismissed to calculated the frame of the outline view.
     // Otherwise the coordinate conversion doesn't give the correct result.
-    [self resignKeyAndDismissViewControllerAnimated:YES completion:^{
+    [self toggleViewsToolWithCompletion:^{
         // If the selected view is outside of the tap point array (selected from "Full Hierarchy"),
         // then clear out the tap point array and remove all the outline views.
         if (![self.viewsAtTapPoint containsObject:selectedView]) {
@@ -835,6 +835,15 @@ typedef NS_ENUM(NSUInteger, FLEXExplorerMode) {
     return self.previousKeyWindow != nil;
 }
 
+- (void)toggleToolWithViewControllerProvider:(UIViewController *(^)())future completion:(void(^)())completion
+{
+    if (self.presentedViewController) {
+        [self resignKeyAndDismissViewControllerAnimated:YES completion:completion];
+    } else {
+        [self makeKeyAndPresentViewController:future() animated:YES completion:completion];
+    }
+}
+
 #pragma mark - Keyboard Shortcut Helpers
 
 - (void)toggleSelectTool
@@ -857,49 +866,32 @@ typedef NS_ENUM(NSUInteger, FLEXExplorerMode) {
 
 - (void)toggleViewsTool
 {
-    BOOL viewsModalShown = [[self presentedViewController] isKindOfClass:[UINavigationController class]];
-    viewsModalShown = viewsModalShown && [[[(UINavigationController *)[self presentedViewController] viewControllers] firstObject] isKindOfClass:[FLEXHierarchyTableViewController class]];
-    if (viewsModalShown) {
-        [self resignKeyAndDismissViewControllerAnimated:YES completion:nil];
-    } else {
-        void (^presentBlock)(void) = ^{
-            NSArray<UIView *> *allViews = [self allViewsInHierarchy];
-            NSDictionary<NSValue *, NSNumber *> *depthsForViews = [self hierarchyDepthsForViews:allViews];
-            FLEXHierarchyTableViewController *hierarchyTVC = [[FLEXHierarchyTableViewController alloc] initWithViews:allViews viewsAtTap:self.viewsAtTapPoint selectedView:self.selectedView depths:depthsForViews];
-            hierarchyTVC.delegate = self;
-            UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:hierarchyTVC];
-            [self makeKeyAndPresentViewController:navigationController animated:YES completion:nil];
-        };
-        
-        if (self.presentedViewController) {
-            [self resignKeyAndDismissViewControllerAnimated:NO completion:presentBlock];
-        } else {
-            presentBlock();
+    [self toggleViewsToolWithCompletion:nil];
+}
+
+- (void)toggleViewsToolWithCompletion:(void(^)())completion
+{
+    [self toggleToolWithViewControllerProvider:^UIViewController *{
+        NSArray<UIView *> *allViews = [self allViewsInHierarchy];
+        NSDictionary *depthsForViews = [self hierarchyDepthsForViews:allViews];
+        FLEXHierarchyTableViewController *hierarchyTVC = [[FLEXHierarchyTableViewController alloc] initWithViews:allViews viewsAtTap:self.viewsAtTapPoint selectedView:self.selectedView depths:depthsForViews];
+        hierarchyTVC.delegate = self;
+        return [[UINavigationController alloc] initWithRootViewController:hierarchyTVC];
+    } completion:^{
+        if (completion) {
+            completion();
         }
-    }
+    }];
 }
 
 - (void)toggleMenuTool
 {
-    BOOL menuModalShown = [[self presentedViewController] isKindOfClass:[UINavigationController class]];
-    menuModalShown = menuModalShown && [[[(UINavigationController *)[self presentedViewController] viewControllers] firstObject] isKindOfClass:[FLEXGlobalsTableViewController class]];
-    if (menuModalShown) {
-        [self resignKeyAndDismissViewControllerAnimated:YES completion:nil];
-    } else {
-        void (^presentBlock)(void) = ^{
-            FLEXGlobalsTableViewController *globalsViewController = [[FLEXGlobalsTableViewController alloc] init];
-            globalsViewController.delegate = self;
-            [FLEXGlobalsTableViewController setApplicationWindow:[[UIApplication sharedApplication] keyWindow]];
-            UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:globalsViewController];
-            [self makeKeyAndPresentViewController:navigationController animated:YES completion:nil];
-        };
-        
-        if (self.presentedViewController) {
-            [self resignKeyAndDismissViewControllerAnimated:NO completion:presentBlock];
-        } else {
-            presentBlock();
-        }
-    }
+    [self toggleToolWithViewControllerProvider:^UIViewController *{
+        FLEXGlobalsTableViewController *globalsViewController = [[FLEXGlobalsTableViewController alloc] init];
+        globalsViewController.delegate = self;
+        [FLEXGlobalsTableViewController setApplicationWindow:[[UIApplication sharedApplication] keyWindow]];
+        return [[UINavigationController alloc] initWithRootViewController:globalsViewController];
+    } completion:nil];
 }
 
 - (void)handleDownArrowKeyPressed