// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CC_BASE_FEATURES_H_
#define CC_BASE_FEATURES_H_
#include <string>
#include "base/feature_list.h"
#include "base/metrics/field_trial_params.h"
#include "build/build_config.h"
#include "cc/base/base_export.h"
namespace features {
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kAnimatedImageResume);
CC_BASE_EXPORT extern bool IsImpulseScrollAnimationEnabled();
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kSynchronizedScrolling);
// Elastic overscroll on Android can change scale causing a lot of raster.
// This is wasteful and visually unnecessary since it's a short animation
// that resets the scale at the end. When enabled, this aovids recomputing
// raster scale during elastic overscroll.
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kAvoidRasterDuringElasticOverscroll);
// When enabled, the double tap to zoom will be disabled when the viewport
// meta tag is properly set for mobile using content=width=device-width
// or content=initial-scale=1.0
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kRemoveMobileViewportDoubleTap);
// When enabled, all scrolling is performed on the compositor thread -
// delegating only the hit test to Blink. This causes Blink to send additional
// information in the scroll property tree. When a scroll can't be hit tested
// on the compositor, it will post a hit test task to Blink and continue the
// scroll when that resolves. For details, see:
// https://docs.google.com/document/d/1smLAXs-DSLLmkEt4FIPP7PVglJXOcwRc7A5G0SEwxaY/edit
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kScrollUnification);
// Sets raster tree priority to NEW_CONTENT_TAKES_PRIORITY when performing a
// unified scroll with main-thread repaint reasons.
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kMainRepaintScrollPrefersNewContent);
// Flush pending GPU raster work before running the LTHI::DrawLayers stage.
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kFlushGpuAtDraw);
// When enabled, wheel scrolls trigger smoothness mode. When disabled,
// smoothness mode is limited to non-animated (precision) scrolls, such as
// touch scrolling.
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kSchedulerSmoothnessForAnimatedScrolls);
// When enabled, cc will show blink's Web-Vital metrics inside its heads up
// display.
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kHudDisplayForPerformanceMetrics);
// Whether RenderSurface::common_ancestor_clip_id() is used to clip to the
// common ancestor clip when any contributing layer escapes the clip of the
// render surface's owning effect.
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kRenderSurfaceCommonAncestorClip);
// When enabled, some jank is injected to the animation/scrolling pipeline.
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kJankInjectionAblationFeature);
// When enabled, scheduler tree priority will change to
// NEW_CONTENT_TAKES_PRIORITY if during a scrollbar scroll, CC has to
// checkerboard.
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kPreferNewContentForCheckerboardedScrolls);
// When enabled, CompositorTimingHistory will directly record the timing history
// that is used to calculate main thread timing estimates, and use the
// percentile of sum of different stages instead of the sum of percentiles.
CC_BASE_EXPORT BASE_DECLARE_FEATURE(
kDurationEstimatesInCompositorTimingHistory);
// When enabled, the main thread does not block while commit is running on the
// impl thread.
// WARNING: This feature is not yet safe to enable. Work is needed to ensure
// that main thread cc data structures are not modified on the main thread while
// commit is running concurrently on the impl thread.
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kNonBlockingCommit);
// When enabled, DroppedFrameCounter will use an adjusted sliding window
// interval specified by field trial params.
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kSlidingWindowForDroppedFrameCounter);
// When enabled, SupportsBackgroundThreadPriority is set to kNo for
// GpuImageDecodeTaskImpl and SoftwareImageDecodeTaskImpl.
// Introduced to fix https://crbug.com/1116624
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kNormalPriorityImageDecoding);
// Use DMSAA instead of MSAA for rastering tiles.
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kUseDMSAAForTiles);
// Updating browser controls state will IPC directly from browser main to the
// compositor thread. Previously this proxied through the renderer main thread.
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kUpdateBrowserControlsWithoutProxy);
// Fix the SMOOTHNESS_TAKES_PRIORITY queue priorities used in
// RasterTilePriorityQueueAll::GetNextQueues(). By fixing the bug which fails to
// schedule raster tasks for Pending SOON tiles, it reduces checkerboarding and
// improves the rendering.desktop tough_scrolling benchmark.
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kRasterTilePriorityQueue);
// Enables shared image cache for gpu used by CC instances instantiated for UI.
// TODO(https://crbug.com/c/1378251): this shall also be possible to use by
// renderers.
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kUIEnableSharedImageCacheForGpu);
// When LayerTreeHostImpl::ReclaimResources() is called in background, trigger a
// flush to actually reclaim resources.
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kReclaimResourcesFlushInBackground);
// Try to play a longer list of ops before giving up in solid color analysis for
// tiles.
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kMoreAggressiveSolidColorDetection);
// Allow CC FrameRateEstimater to reduce the frame rate to half of the default
// if the condition meets the requirement.
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kReducedFrameRateEstimation);
// Currently there is a race between OnBeginFrames from the GPU process and
// input arriving from the Browser process. Due to this we can start to produce
// a frame while scrolling without any input events. Late arriving events are
// then enqueued for the next VSync.
//
// When this feature is enabled we will use the corresponding mode definted by
// `kScrollEventDispatchModeParamName`.
CC_BASE_EXPORT BASE_DECLARE_FEATURE(kWaitForLateScrollEvents);
CC_BASE_EXPORT extern const base::FeatureParam<double>
kWaitForLateScrollEventsDeadlineRatio;
// Modes for `kWaitForLateScrollEvents` changing event dispatch. Where the
// default is to just always enqueue scroll events.
//
// `kScrollEventDispatchModeNameDispatchScrollEventsImmediately` will wait for
// `kWaitForLateScrollEventsDeadlineRatio` of the frame interval for input.
// During this time scroll events will be dispatched immediately. At the
// deadline we will resume frame production and enqueuing input.
//
// `kScrollEventDispatchModeNameUseScrollPredictorForEmptyQueue` checks when
// we begin frame production, if the event queue is empty, we will generate a
// new prediction and dispatch a synthetic scroll event.
//
// `kScrollEventDispatchModeUseScrollPredictorForDeadline` will perform the
// same as `kScrollEventDispatchModeDispatchScrollEventsImmediately` until
// the deadline is encountered. Instead of immediately resuming frame
// production, we will first attempt to generate a new prediction to dispatch.
// As in `kScrollEventDispatchModeUseScrollPredictorForEmptyQueue`. After
// which we will resume frame production and enqueuing input.
CC_BASE_EXPORT extern const base::FeatureParam<std::string>
kScrollEventDispatchMode;
CC_BASE_EXPORT extern const char
kScrollEventDispatchModeEnqueueScrollEvents[];
CC_BASE_EXPORT extern const char
kScrollEventDispatchModeDispatchScrollEventsImmediately[];
CC_BASE_EXPORT extern const char
kScrollEventDispatchModeUseScrollPredictorForEmptyQueue[];
CC_BASE_EXPORT extern const char
kScrollEventDispatchModeUseScrollPredictorForDeadline[];
} // namespace features
#endif // CC_BASE_FEATURES_H_