[iOS] Added FullscreenViewportInsetRangeChanged().

This callback can be used to notify FullscreenControllerObservers of
changes to the viewport inset range.  It can be used to trigger a
viewport adjustment for new toolbar heights.

Bug: 674649
Change-Id: I4ecdc374c1017716518118a27d4b9c5e0f1db48f
Reviewed-on: https://chromium-review.googlesource.com/c/1340953
Commit-Queue: Kurt Horimoto <kkhorimoto@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#613313}

ios/chrome/browser/ui/fullscreen/fullscreen_controller_observer.h

@@ -5,7 +5,7 @@
 #ifndef IOS_CLEAN_CHROME_BROWSER_UI_FULLSCREEN_FULLSCREEN_CONTROLLER_OBSERVER_H_
 #define IOS_CLEAN_CHROME_BROWSER_UI_FULLSCREEN_FULLSCREEN_CONTROLLER_OBSERVER_H_
 
-#include <CoreGraphics/CoreGraphics.h>
+#import <UIKit/UIKit.h>
 
 #include "base/macros.h"
 
@@ -18,6 +18,11 @@ class FullscreenControllerObserver {
   FullscreenControllerObserver() = default;
   virtual ~FullscreenControllerObserver() = default;
 
+  // Invoked when the maximum or minimum viewport insets for |controller| have
+  // been updated.
+  virtual void FullscreenViewportInsetRangeChanged(
+      FullscreenController* controller) {}
+
   // Invoked after a scrolling event has caused |controller| to calculate
   // |progress|.  A |progress| value of 1.0 denotes that the toolbar should be
   // completely visible, while a |progress| value of 0.0 denotes that the

ios/chrome/browser/ui/fullscreen/fullscreen_mediator.h

@@ -52,6 +52,7 @@ class FullscreenMediator : public FullscreenModelObserver {
 
  private:
   // FullscreenModelObserver:
+  void FullscreenModelToolbarHeightsUpdated(FullscreenModel* model) override;
   void FullscreenModelProgressUpdated(FullscreenModel* model) override;
   void FullscreenModelEnabledStateChanged(FullscreenModel* model) override;
   void FullscreenModelScrollEventStarted(FullscreenModel* model) override;

ios/chrome/browser/ui/fullscreen/fullscreen_mediator.mm

@@ -63,6 +63,13 @@ void FullscreenMediator::Disconnect() {
   controller_ = nullptr;
 }
 
+void FullscreenMediator::FullscreenModelToolbarHeightsUpdated(
+    FullscreenModel* model) {
+  for (auto& observer : observers_) {
+    observer.FullscreenViewportInsetRangeChanged(controller_);
+  }
+}
+
 void FullscreenMediator::FullscreenModelProgressUpdated(
     FullscreenModel* model) {
   DCHECK_EQ(model_, model);

ios/chrome/browser/ui/fullscreen/fullscreen_mediator_unittest.mm

@@ -63,3 +63,22 @@ TEST_F(FullscreenMediatorTest, ObserveEnabledState) {
   model().DecrementDisabledCounter();
   EXPECT_TRUE(observer().enabled());
 }
+
+// Tests that changes to the model's toolbar heights are forwarded to observers.
+TEST_F(FullscreenMediatorTest, ObserveViewportInsets) {
+  const CGFloat kExpandedHeight = 100.0;
+  const CGFloat kCollapsedHeight = 50.0;
+  const CGFloat kBottomHeight = 60.0;
+  model().SetExpandedToolbarHeight(kExpandedHeight);
+  model().SetCollapsedToolbarHeight(kCollapsedHeight);
+  model().SetBottomToolbarHeight(kBottomHeight);
+  EXPECT_TRUE(UIEdgeInsetsEqualToEdgeInsets(
+      observer().min_viewport_insets(),
+      UIEdgeInsetsMake(kCollapsedHeight, 0, 0, 0)));
+  EXPECT_TRUE(UIEdgeInsetsEqualToEdgeInsets(
+      observer().max_viewport_insets(),
+      UIEdgeInsetsMake(kExpandedHeight, 0, kBottomHeight, 0)));
+  EXPECT_TRUE(UIEdgeInsetsEqualToEdgeInsets(
+      observer().current_viewport_insets(),
+      UIEdgeInsetsMake(kExpandedHeight, 0, kBottomHeight, 0)));
+}

ios/chrome/browser/ui/fullscreen/fullscreen_model.mm

@@ -84,6 +84,10 @@ void FullscreenModel::SetCollapsedToolbarHeight(CGFloat height) {
   DCHECK_GE(height, 0.0);
   collapsed_toolbar_height_ = height;
   ResetForNavigation();
+  ScopedIncrementer toolbar_height_incrementer(&observer_callback_count_);
+  for (auto& observer : observers_) {
+    observer.FullscreenModelToolbarHeightsUpdated(this);
+  }
 }
 
 CGFloat FullscreenModel::GetCollapsedToolbarHeight() const {
@@ -96,6 +100,10 @@ void FullscreenModel::SetExpandedToolbarHeight(CGFloat height) {
   DCHECK_GE(height, 0.0);
   expanded_toolbar_height_ = height;
   ResetForNavigation();
+  ScopedIncrementer toolbar_height_incrementer(&observer_callback_count_);
+  for (auto& observer : observers_) {
+    observer.FullscreenModelToolbarHeightsUpdated(this);
+  }
 }
 
 CGFloat FullscreenModel::GetExpandedToolbarHeight() const {
@@ -108,6 +116,10 @@ void FullscreenModel::SetBottomToolbarHeight(CGFloat height) {
   DCHECK_GE(height, 0.0);
   bottom_toolbar_height_ = height;
   ResetForNavigation();
+  ScopedIncrementer toolbar_height_incrementer(&observer_callback_count_);
+  for (auto& observer : observers_) {
+    observer.FullscreenModelToolbarHeightsUpdated(this);
+  }
 }
 
 CGFloat FullscreenModel::GetBottomToolbarHeight() const {

ios/chrome/browser/ui/fullscreen/fullscreen_model_observer.h

@@ -17,6 +17,9 @@ class FullscreenModelObserver {
   FullscreenModelObserver() = default;
   virtual ~FullscreenModelObserver() = default;
 
+  // Invoked when |model|'s toolbar heights have been updated.
+  virtual void FullscreenModelToolbarHeightsUpdated(FullscreenModel* model) {}
+
   // Invoked when |model|'s calculated progress() value is updated.
   virtual void FullscreenModelProgressUpdated(FullscreenModel* model) {}
 

ios/chrome/browser/ui/fullscreen/test/test_fullscreen_controller_observer.h

@@ -10,6 +10,11 @@
 // Test version of FullscreenControllerObserver.
 class TestFullscreenControllerObserver : public FullscreenControllerObserver {
  public:
+  UIEdgeInsets min_viewport_insets() const { return min_viewport_insets_; }
+  UIEdgeInsets max_viewport_insets() const { return max_viewport_insets_; }
+  UIEdgeInsets current_viewport_insets() const {
+    return current_viewport_insets_;
+  }
   CGFloat progress() const { return progress_; }
   bool enabled() const { return enabled_; }
   FullscreenAnimator* animator() const { return animator_; }
@@ -17,6 +22,8 @@ class TestFullscreenControllerObserver : public FullscreenControllerObserver {
 
  private:
   // FullscreenControllerObserver:
+  void FullscreenViewportInsetRangeChanged(
+      FullscreenController* controller) override;
   void FullscreenProgressUpdated(FullscreenController* controller,
                                  CGFloat progress) override;
   void FullscreenEnabledStateChanged(FullscreenController* controller,
@@ -26,6 +33,9 @@ class TestFullscreenControllerObserver : public FullscreenControllerObserver {
   void FullscreenControllerWillShutDown(
       FullscreenController* controller) override;
 
+  UIEdgeInsets min_viewport_insets_ = UIEdgeInsetsZero;
+  UIEdgeInsets max_viewport_insets_ = UIEdgeInsetsZero;
+  UIEdgeInsets current_viewport_insets_ = UIEdgeInsetsZero;
   CGFloat progress_ = 0.0;
   bool enabled_ = true;
   __weak FullscreenAnimator* animator_ = nil;

ios/chrome/browser/ui/fullscreen/test/test_fullscreen_controller_observer.mm

@@ -11,6 +11,13 @@
 #error "This file requires ARC support."
 #endif
 
+void TestFullscreenControllerObserver::FullscreenViewportInsetRangeChanged(
+    FullscreenController* controller) {
+  min_viewport_insets_ = controller->GetMinViewportInsets();
+  max_viewport_insets_ = controller->GetMaxViewportInsets();
+  current_viewport_insets_ = controller->GetCurrentViewportInsets();
+}
+
 void TestFullscreenControllerObserver::FullscreenProgressUpdated(
     FullscreenController* controller,
     CGFloat progress) {