Unify Android Webview and Chrome's fling

android_webview/browser/browser_view_renderer.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "android_webview/browser/browser_view_renderer.h"
 
 #include "android_webview/browser/browser_view_renderer_client.h"
 #include "android_webview/browser/child_frame.h"
 #include "base/auto_reset.h"
 #include "base/command_line.h"
@@ skipping 396 matching lines @@
 }
 
 void BrowserViewRenderer::OnDetachedFromWindow() {
   TRACE_EVENT0("android_webview", "BrowserViewRenderer::OnDetachedFromWindow");
   shared_renderer_state_.ReleaseHardwareDrawIfNeededOnUI();
   attached_to_window_ = false;
   DCHECK(!hardware_enabled_);
   UpdateCompositorIsActive();
 }
 
+void BrowserViewRenderer::OnComputeScroll(base::TimeTicks animation_time) {
+  if (pending_fling_animation_.is_null())
+    return;
+  FlushPendingFlingAnimation(animation_time);
+}
+
 void BrowserViewRenderer::ReleaseHardware() {
   DCHECK(hardware_enabled_);
   ReturnUnusedResource(shared_renderer_state_.PassUncommittedFrameOnUI());
   ReturnResourceFromParent();
   DCHECK(shared_renderer_state_.ReturnedResourcesEmptyOnUI());
 
   if (compositor_) {
     compositor_->SetMemoryPolicy(0u);
   }
 
@@ skipping 116 matching lines @@
   DCHECK_LE(scroll_offset.x(), max_offset.x());
   DCHECK_LE(scroll_offset.y(), max_offset.y());
 
   client_->ScrollContainerViewTo(scroll_offset);
 }
 
 gfx::Vector2dF BrowserViewRenderer::GetTotalRootLayerScrollOffset() {
   return scroll_offset_dip_;
 }
 
-bool BrowserViewRenderer::IsExternalFlingActive() const {
-  return client_->IsFlingActive();
+bool BrowserViewRenderer::IsExternalScrollActive() const {
+  return client_->IsSmoothScrollingActive();
 }
 
 void BrowserViewRenderer::UpdateRootLayerState(
     const gfx::Vector2dF& total_scroll_offset_dip,
     const gfx::Vector2dF& max_scroll_offset_dip,
     const gfx::SizeF& scrollable_size_dip,
     float page_scale_factor,
     float min_page_scale_factor,
     float max_page_scale_factor) {
   TRACE_EVENT_INSTANT1(
@@ skipping 33 matching lines @@
   state->SetDouble("max_scroll_offset_dip.x", max_scroll_offset_dip_.x());
   state->SetDouble("max_scroll_offset_dip.y", max_scroll_offset_dip_.y());
 
   state->SetDouble("scrollable_size_dip.width", scrollable_size_dip.width());
   state->SetDouble("scrollable_size_dip.height", scrollable_size_dip.height());
 
   state->SetDouble("page_scale_factor", page_scale_factor_);
   return state;
 }
 
+void BrowserViewRenderer::SetNeedsAnimateFling(
+    const AnimationCallback& fling_animation) {
+  // TODO(jdduke): Skip invalidate if animation already pending?

[aelias_OOO_until_Jul13, 2015/05/09 03:32:04]

Resolve this TODO one way or the other?  Personally, I think there's probably no
harm in extra invalidates.

[hush (inactive), 2015/05/12 19:08:45]

I will just remove this TODO.

+  pending_fling_animation_ = fling_animation;
+  client_->PostInvalidate();
+}
+
 void BrowserViewRenderer::DidOverscroll(gfx::Vector2dF accumulated_overscroll,
                                         gfx::Vector2dF latest_overscroll_delta,
                                         gfx::Vector2dF current_fling_velocity) {
   const float physical_pixel_scale = dip_scale_ * page_scale_factor_;
   if (accumulated_overscroll == latest_overscroll_delta)
     overscroll_rounding_error_ = gfx::Vector2dF();
   gfx::Vector2dF scaled_overscroll_delta =
       gfx::ScaleVector2d(latest_overscroll_delta, physical_pixel_scale);
   gfx::Vector2d rounded_overscroll_delta = gfx::ToRoundedVector2d(
       scaled_overscroll_delta + overscroll_rounding_error_);
   overscroll_rounding_error_ =
       scaled_overscroll_delta - rounded_overscroll_delta;
-  client_->DidOverscroll(rounded_overscroll_delta);
+
+  gfx::Vector2dF fling_velocity_pixels =
+      gfx::ScaleVector2d(current_fling_velocity, physical_pixel_scale);
+
+  const bool first_overscroll_x =
+      accumulated_overscroll.x() &&
+      accumulated_overscroll.x() == latest_overscroll_delta.x();
+  const bool first_overscroll_y =
+      accumulated_overscroll.y() &&
+      accumulated_overscroll.y() == latest_overscroll_delta.y();
+
+  client_->DidOverscroll(rounded_overscroll_delta, fling_velocity_pixels,
+                         first_overscroll_x, first_overscroll_y);
 }
 
 void BrowserViewRenderer::PostInvalidate() {
   TRACE_EVENT_INSTANT0("android_webview", "BrowserViewRenderer::PostInvalidate",
                        TRACE_EVENT_SCOPE_THREAD);
   PostInvalidateWithFallback();
 }
 
 void BrowserViewRenderer::PostInvalidateWithFallback() {
   // Always call view invalidate. We rely the Android framework to ignore the
@@ skipping 56 matching lines @@
 
 void BrowserViewRenderer::ForceFakeCompositeSW() {
   DCHECK(compositor_);
   SkBitmap bitmap;
   bitmap.allocN32Pixels(1, 1);
   bitmap.eraseColor(0);
   SkCanvas canvas(bitmap);
   CompositeSW(&canvas);
 }
 
+void BrowserViewRenderer::FlushPendingFlingAnimation(
+    base::TimeTicks animation_time) {
+  TRACE_EVENT0("android_webview",
+               "BrowserViewRenderer::FlushPendingFlingAnimation");
+  DCHECK(!pending_fling_animation_.is_null());
+  AnimationCallback animation = pending_fling_animation_;
+  pending_fling_animation_.Reset();
+  animation.Run(animation_time);
+}
+
 bool BrowserViewRenderer::CompositeSW(SkCanvas* canvas) {
   DCHECK(compositor_);
   CancelFallbackTick();
   ReturnResourceFromParent();
   return compositor_->DemandDrawSw(canvas);
 }
 
 void BrowserViewRenderer::UpdateCompositorIsActive() {
   if (compositor_)
     compositor_->SetIsActive(!is_paused_ &&
@@ skipping 19 matching lines @@
   base::StringAppendF(&str,
                       "overscroll_rounding_error_: %s ",
                       overscroll_rounding_error_.ToString().c_str());
   base::StringAppendF(
       &str, "on_new_picture_enable: %d ", on_new_picture_enable_);
   base::StringAppendF(&str, "clear_view: %d ", clear_view_);
   return str;
 }
 
 }  // namespace android_webview