Refactor GestureNavigation to eliminate code redundancy

content/browser/web_contents/aura/overscroll_navigation_overlay.cc

Index: content/browser/web_contents/aura/overscroll_navigation_overlay.cc
diff --git a/content/browser/web_contents/aura/overscroll_navigation_overlay.cc b/content/browser/web_contents/aura/overscroll_navigation_overlay.cc
index 8948f9a8bfed397db4fc40ebb316dc79c1db6482..28e71bd9b0ea7941df3f79aa0b428f4e57ae80f4 100644
--- a/content/browser/web_contents/aura/overscroll_navigation_overlay.cc
+++ b/content/browser/web_contents/aura/overscroll_navigation_overlay.cc
@@ -4,14 +4,17 @@
 
 #include "content/browser/web_contents/aura/overscroll_navigation_overlay.h"
 
+#include <vector>
+
+#include "base/i18n/rtl.h"
 #include "content/browser/frame_host/navigation_entry_impl.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
+#include "content/browser/web_contents/aura/overscroll_window_delegate.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/common/view_messages.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/render_widget_host_view.h"
 #include "ui/aura/window.h"
-#include "ui/aura_extra/image_window_delegate.h"
 #include "ui/base/layout.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/layer_animation_observer.h"
@@ -19,7 +22,6 @@
 #include "ui/compositor/scoped_layer_animation_settings.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/image/image_png_rep.h"
-#include "ui/gfx/image/image_skia.h"
 
 namespace content {
 namespace {
@@ -43,50 +45,20 @@ bool DoesEntryMatchURL(NavigationEntry* entry, const GURL& url) {
 
 }  // namespace
 
-// A LayerDelegate that paints an image for the layer.
-class ImageLayerDelegate : public ui::LayerDelegate {
+// A class that sets masks to bounds to false on a layer and restores the old
+// value on destruction.
+class OverscrollNavigationOverlay::ScopedLayerClippingSetting {
  public:
-  ImageLayerDelegate() {}
-
-  ~ImageLayerDelegate() override {}
-
-  void SetImage(const gfx::Image& image) {
-    image_ = image;
-    image_size_ = image.AsImageSkia().size();
-  }
-  const gfx::Image& image() const { return image_; }
-
- private:
-  // Overridden from ui::LayerDelegate:
-  void OnPaintLayer(const ui::PaintContext& context) override {
-    ui::PaintRecorder recorder(context);
-    if (image_.IsEmpty()) {
-      recorder.canvas()->DrawColor(SK_ColorWHITE);
-    } else {
-      SkISize size = recorder.canvas()->sk_canvas()->getDeviceSize();
-      if (size.width() != image_size_.width() ||
-          size.height() != image_size_.height()) {
-        recorder.canvas()->DrawColor(SK_ColorWHITE);
-      }
-      recorder.canvas()->DrawImageInt(image_.AsImageSkia(), 0, 0);
-    }
+  explicit ScopedLayerClippingSetting(ui::Layer* layer)
+      : masks_to_bounds_(layer->GetMasksToBounds()), layer_(layer) {
+    layer_->SetMasksToBounds(false);
   }
 
-  void OnDelegatedFrameDamage(const gfx::Rect& damage_rect_in_dip) override {}
+  ~ScopedLayerClippingSetting() { layer_->SetMasksToBounds(masks_to_bounds_); }
 
-  // Called when the layer's device scale factor has changed.
-  void OnDeviceScaleFactorChanged(float device_scale_factor) override {}
-
-  // Invoked prior to the bounds changing. The returned closured is run after
-  // the bounds change.
-  base::Closure PrepareForLayerBoundsChange() override {
-    return base::Closure();
-  }
-
-  gfx::Image image_;
-  gfx::Size image_size_;
-
-  DISALLOW_COPY_AND_ASSIGN(ImageLayerDelegate);
+ private:
+  bool masks_to_bounds_;
+  ui::Layer* layer_;
 };
 
 // Responsible for fading out and deleting the layer of the overlay window.
@@ -132,27 +104,27 @@ class OverlayDismissAnimator
 };
 
 OverscrollNavigationOverlay::OverscrollNavigationOverlay(
-    WebContentsImpl* web_contents)
-    : web_contents_(web_contents),
-      image_delegate_(NULL),
+    WebContentsImpl* web_contents,
+    aura::Window* web_contents_window)
+    : direction_(NONE),
+      web_contents_(web_contents),
       loading_complete_(false),
       received_paint_update_(false),
-      slide_direction_(SLIDE_UNKNOWN) {
+      owa_(new OverscrollWindowAnimation(this)),
+      web_contents_window_(web_contents_window) {
 }
 
 OverscrollNavigationOverlay::~OverscrollNavigationOverlay() {
+  aura::Window* event_window = GetMainWindow();
+  if (owa_->is_active() && event_window)
+    event_window->ReleaseCapture();
 }
 
 void OverscrollNavigationOverlay::StartObserving() {
   loading_complete_ = false;
   received_paint_update_ = false;
-  overlay_dismiss_layer_.reset();
   Observe(web_contents_);
 
-  // Make sure the overlay window is on top.
-  if (window_.get() && window_->parent())
-    window_->parent()->StackChildAtTop(window_.get());
-
   // Assumes the navigation has been initiated.
   NavigationEntry* pending_entry =
       web_contents_->GetController().GetPendingEntry();
@@ -162,140 +134,133 @@ void OverscrollNavigationOverlay::StartObserving() {
   pending_entry_url_ = pending_entry ? pending_entry->GetURL() : GURL();
 }
 
-void OverscrollNavigationOverlay::SetOverlayWindow(
-    scoped_ptr<aura::Window> window,
-    aura_extra::ImageWindowDelegate* delegate) {
-  window_ = window.Pass();
-  if (window_.get() && window_->parent())
-    window_->parent()->StackChildAtTop(window_.get());
-  image_delegate_ = delegate;
-
-  if (window_.get() && delegate->has_image()) {
-    window_slider_.reset(new WindowSlider(this,
-                                          window_->parent(),
-                                          window_.get()));
-    slide_direction_ = SLIDE_UNKNOWN;
-  } else {
-    window_slider_.reset();
-  }
-}
-
 void OverscrollNavigationOverlay::StopObservingIfDone() {
   // Normally we dismiss the overlay once we receive a paint update, however
   // for in-page navigations DidFirstVisuallyNonEmptyPaint() does not get
   // called, and we rely on loading_complete_ for those cases.
-  if (!received_paint_update_ && !loading_complete_)
-    return;
-
-  // If a slide is in progress, then do not destroy the window or the slide.
-  if (window_slider_.get() && window_slider_->IsSlideInProgress())
+  // If an overscroll gesture is in progress, then do not destroy the window.
+  if (!window_ || !(loading_complete_ || received_paint_update_) ||
+      owa_->is_active()) {
     return;
+  }
+  // Restore layer clipping.
+  contents_layer_settings_.reset();
+  contents_layer_parent_settings_.reset();
 
-  // The layer to be animated by OverlayDismissAnimator
-  scoped_ptr<ui::Layer> overlay_dismiss_layer;
-  if (overlay_dismiss_layer_)
-    overlay_dismiss_layer = overlay_dismiss_layer_.Pass();
-  else if (window_.get())
-    overlay_dismiss_layer = window_->AcquireLayer();
-  Observe(NULL);
-  window_slider_.reset();
+  // OverlayDismissAnimator deletes the dismiss layer and itself when the
+  // animation completes.
+  scoped_ptr<ui::Layer> dismiss_layer = window_->AcquireLayer();
   window_.reset();
-  image_delegate_ = NULL;
-  if (overlay_dismiss_layer.get()) {
-    // OverlayDismissAnimator deletes overlay_dismiss_layer and itself when the
-    // animation completes.
-    (new OverlayDismissAnimator(overlay_dismiss_layer.Pass()))->Animate();
-  }
+  (new OverlayDismissAnimator(dismiss_layer.Pass()))->Animate();
+  Observe(nullptr);
+  received_paint_update_ = false;
+  loading_complete_ = false;
 }
 
-ui::Layer* OverscrollNavigationOverlay::CreateSlideLayer(int offset) {
+scoped_ptr<aura::Window> OverscrollNavigationOverlay::CreateOverlayWindow(
+    const gfx::Rect& bounds) {
+  OverscrollWindowDelegate* overscroll_delegate = new OverscrollWindowDelegate(
+      owa_.get(), GetImageForDirection(direction_));
+  scoped_ptr<aura::Window> window(new aura::Window(overscroll_delegate));
+  window->SetTransparent(true);
+  window->Init(ui::LAYER_TEXTURED);
+  window->layer()->SetMasksToBounds(false);
+  window->SetName("OverscrollOverlay");
+  web_contents_window_->AddChild(window.get());
+  aura::Window* event_window = GetMainWindow();
+  if (direction_ == FORWARD)
+    web_contents_window_->StackChildAbove(window.get(), event_window);
+  else
+    web_contents_window_->StackChildBelow(window.get(), event_window);
+  window->SetBounds(bounds);
+  // Set capture on the window that is receiving the overscroll events so that
+  // trackpad scroll gestures keep targetting it even if the mouse pointer moves
+  // off its bounds.
+  event_window->SetCapture();
+  window->Show();

[sadrul, 2015/04/09 19:41:24]

By default, aura Windows are owned by their parents (and so when the parent
dies, it takes all its children with it to the grave). Since in this case, you
are explicitly passing ownership of the window to OWA, you should set
Window::set_owned_by_parent to false here.

[Nina, 2015/04/09 20:18:54]

Done.

+  return window.Pass();
+}
+
+const gfx::Image OverscrollNavigationOverlay::GetImageForDirection(
+    NavigationDirection direction) const {
   const NavigationControllerImpl& controller = web_contents_->GetController();
-  const NavigationEntryImpl* entry = controller.GetEntryAtOffset(offset);
+  const NavigationEntryImpl* entry = NavigationEntryImpl::FromNavigationEntry(
+      controller.GetEntryAtOffset(direction == FORWARD ? 1 : -1));
 
-  gfx::Image image;
   if (entry && entry->screenshot().get()) {
     std::vector<gfx::ImagePNGRep> image_reps;
     image_reps.push_back(gfx::ImagePNGRep(entry->screenshot(), 1.0f));
-    image = gfx::Image(image_reps);
+    return gfx::Image(image_reps);
   }
-  if (!layer_delegate_)
-    layer_delegate_.reset(new ImageLayerDelegate());
-  layer_delegate_->SetImage(image);
+  return gfx::Image();
+}
 
-  ui::Layer* layer = new ui::Layer(ui::LAYER_TEXTURED);
-  layer->set_delegate(layer_delegate_.get());
-  return layer;
+scoped_ptr<aura::Window> OverscrollNavigationOverlay::CreateFrontWindow(
+    const gfx::Rect& bounds) {
+  if (!web_contents_->GetController().CanGoForward())
+    return nullptr;
+  direction_ = FORWARD;
+  return CreateOverlayWindow(bounds);
 }
 
-ui::Layer* OverscrollNavigationOverlay::CreateBackLayer() {
+scoped_ptr<aura::Window> OverscrollNavigationOverlay::CreateBackWindow(
+    const gfx::Rect& bounds) {
   if (!web_contents_->GetController().CanGoBack())
-    return NULL;
-  slide_direction_ = SLIDE_BACK;
-  return CreateSlideLayer(-1);
+    return nullptr;
+  direction_ = BACK;
+  return CreateOverlayWindow(bounds);
 }
 
-ui::Layer* OverscrollNavigationOverlay::CreateFrontLayer() {
-  if (!web_contents_->GetController().CanGoForward())
-    return NULL;
-  slide_direction_ = SLIDE_FRONT;
-  return CreateSlideLayer(1);
+aura::Window* OverscrollNavigationOverlay::GetMainWindow() const {
+  if (window_)
+    return window_.get();
+  return web_contents_->IsBeingDestroyed()
+             ? nullptr
+             : web_contents_->GetContentNativeView();
 }
 
-void OverscrollNavigationOverlay::OnWindowSlideCompleting() {
-  if (slide_direction_ == SLIDE_UNKNOWN)
-    return;
-
-  // Perform the navigation.
-  if (slide_direction_ == SLIDE_BACK)
-    web_contents_->GetController().GoBack();
-  else if (slide_direction_ == SLIDE_FRONT)
+void OverscrollNavigationOverlay::OnOverscrollCompleting() {
+  GetMainWindow()->ReleaseCapture();
+  // We start the navigation as soon as we know the overscroll gesture is
+  // completing.
+  DCHECK(direction_ != NONE);
+
+  // Avoid clipping on the screenshot caused by the contents window being moved
+  // outside of the screen bounds.
+  contents_layer_settings_.reset(
+      new ScopedLayerClippingSetting(web_contents_->GetNativeView()->layer()));
+  contents_layer_parent_settings_.reset(new ScopedLayerClippingSetting(
+      web_contents_->GetNativeView()->layer()->parent()));
+
+  // Make sure we can navigate first, as other factors can trigger a navigation
+  // during an overscroll gesture and navigating without history produces a
+  // crash.
+  if (direction_ == FORWARD && web_contents_->GetController().CanGoForward())
     web_contents_->GetController().GoForward();
-  else
-    NOTREACHED();
-
-  // Reset state and wait for the new navigation page to complete
-  // loading/painting.
+  if (direction_ == BACK && web_contents_->GetController().CanGoBack())
+    web_contents_->GetController().GoBack();
   StartObserving();
 }
 
-void OverscrollNavigationOverlay::OnWindowSlideCompleted(
-    scoped_ptr<ui::Layer> layer) {
-  if (slide_direction_ == SLIDE_UNKNOWN) {
-    window_slider_.reset();
-    StopObservingIfDone();
-    return;
-  }
-
-  // Change the image used for the overlay window.
-  image_delegate_->SetImage(layer_delegate_->image());
-  window_->layer()->SetTransform(gfx::Transform());
-  window_->SchedulePaintInRect(gfx::Rect(window_->bounds().size()));
-  slide_direction_ = SLIDE_UNKNOWN;
-  // We may end up dismissing the overlay before it has a chance to repaint, so
-  // set the slider layer to be the one animated by OverlayDismissAnimator.
-  if (layer.get())
-    overlay_dismiss_layer_ = layer.Pass();
+void OverscrollNavigationOverlay::OnOverscrollCompleted(
+    scoped_ptr<aura::Window> window) {
+  GetMainWindow()->SetTransform(gfx::Transform());
+  window_ = window.Pass();
+  // Make sure the window is in its default position.
+  window_->SetBounds(gfx::Rect(web_contents_window_->bounds().size()));
+  window_->SetTransform(gfx::Transform());
+  // Make sure the overlay window is on top.
+  web_contents_window_->StackChildAtTop(window_.get());
+  direction_ = NONE;
   StopObservingIfDone();
 }
 
-void OverscrollNavigationOverlay::OnWindowSlideAborted() {
+void OverscrollNavigationOverlay::OnOverscrollCancelled() {
+  GetMainWindow()->ReleaseCapture();
+  direction_ = NONE;
   StopObservingIfDone();
 }
 
-void OverscrollNavigationOverlay::OnWindowSliderDestroyed() {
-  // We only want to take an action here if WindowSlider is being destroyed
-  // outside of OverscrollNavigationOverlay. If window_slider_.get() is NULL,
-  // then OverscrollNavigationOverlay is the one destroying WindowSlider, and
-  // we don't need to do anything.
-  // This check prevents StopObservingIfDone() being called multiple times
-  // (including recursively) for a single event.
-  if (window_slider_.get()) {
-    // The slider has just been destroyed. Release the ownership.
-    ignore_result(window_slider_.release());
-    StopObservingIfDone();
-  }
-}
-
 void OverscrollNavigationOverlay::DidFirstVisuallyNonEmptyPaint() {
   NavigationEntry* visible_entry =
       web_contents_->GetController().GetVisibleEntry();
@@ -309,7 +274,7 @@ void OverscrollNavigationOverlay::DidFirstVisuallyNonEmptyPaint() {
 void OverscrollNavigationOverlay::DidStopLoading() {
   // Don't compare URLs in this case - it's possible they won't match if
   // a gesture-nav initiated navigation was interrupted by some other in-site
-  // navigation ((e.g., from a script, or from a bookmark).
+  // navigation (e.g., from a script, or from a bookmark).
   loading_complete_ = true;
   StopObservingIfDone();
 }