DrawOcclusion: Unify flags to enable draw occlusion

DrawOcclusion can be enabled with both flags --enable-draw-occlusion and
--enable-features=DrawOcclusion. This cl unifies the two existing flags,
so the it can only be enabled with --enable-features=DrawOcclusion.

Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel
Change-Id: Ib6deef4da8bdbd31fa62380c8bd6de2a97851d12
Reviewed-on: https://chromium-review.googlesource.com/917664Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Reviewed-by: Fady Samuel <fsamuel@chromium.org>
Commit-Queue: Yi Xu <yiyix@chromium.org>
Cr-Commit-Position: refs/heads/master@{#536770}

chrome/browser/about_flags.cc

@@ -1217,7 +1217,7 @@ const FeatureEntry kFeatureEntries[] = {
      SINGLE_VALUE_TYPE(switches::kShowOverdrawFeedback)},
     {"enable-draw-occlusion", flag_descriptions::kEnableDrawOcclusionName,
      flag_descriptions::kEnableDrawOcclusionDescription, kOsAll,
-     SINGLE_VALUE_TYPE(switches::kEnableDrawOcclusion)},
+     FEATURE_VALUE_TYPE(features::kEnableDrawOcclusion)},
     {"ui-disable-partial-swap", flag_descriptions::kUiPartialSwapName,
      flag_descriptions::kUiPartialSwapDescription, kOsAll,
      SINGLE_DISABLE_VALUE_TYPE(switches::kUIDisablePartialSwap)},

components/viz/common/features.cc

@@ -9,8 +9,6 @@
 
 namespace features {
 
-const char kUIEnableDrawOcclusion[] = "enable-draw-occlusion";
-
 // Enables running draw occlusion algorithm to remove Draw Quads that are not
 // shown on screen from CompositorFrame.
 const base::Feature kEnableDrawOcclusion{"DrawOcclusion",
@@ -58,9 +56,7 @@ bool IsVizHitTestingSurfaceLayerEnabled() {
 }
 
 bool IsDrawOcclusionEnabled() {
-  return base::CommandLine::ForCurrentProcess()->HasSwitch(
-             kUIEnableDrawOcclusion) ||
-         base::FeatureList::IsEnabled(kEnableDrawOcclusion);
+  return base::FeatureList::IsEnabled(kEnableDrawOcclusion);
 }
 
 }  // namespace features

tools/metrics/histograms/enums.xml

@@ -25919,7 +25919,6 @@ from previous Chrome versions.
       label="AutofillToolkitViewsCreditCardDialogsMac:disabled"/>
   <int value="-802348444" label="disable-site-engagement-service"/>
   <int value="-798187384" label="try-supported-channel-layouts"/>
-  <int value="-795854288" label="enable-draw-occlusion"/>
   <int value="-795600188" label="disable-async-dns"/>
   <int value="-793921836" label="ShowAllDialogsWithViewsToolkit:disabled"/>
   <int value="-790036192" label="overscroll-start-threshold"/>
@@ -26412,6 +26411,7 @@ from previous Chrome versions.
   <int value="492985975" label="use-monitor-color-space"/>
   <int value="493903641" label="disable-appcontainer"/>
   <int value="494733611" label="disable-drop-sync-credential"/>
+  <int value="501477022" label="DrawOcclusion:enabled"/>
   <int value="503245473" label="disable-translate-new-ux"/>
   <int value="504994663" label="GenericSensor:disabled"/>
   <int value="506680761" label="WebNFC:disabled"/>
@@ -26588,6 +26588,7 @@ from previous Chrome versions.
   <int value="952558794" label="enable-remote-assistance"/>
   <int value="955340765" label="ChromeHomeOptOutSnackbar:enabled"/>
   <int value="963457392" label="ChromeHomeModernLayout:disabled"/>
+  <int value="963671232" label="DrawOcclusion:disabled"/>
   <int value="975104092" label="show-taps"/>
   <int value="979445973" label="OmniboxSpareRenderer:enabled"/>
   <int value="980396200" label="enable-new-korean-ime"/>

ui/base/ui_base_switches.cc

@@ -104,9 +104,6 @@ const char kUIDisablePartialSwap[] = "ui-disable-partial-swap";
 // Red: Overdrawn four or more times.
 const char kShowOverdrawFeedback[] = "show-overdraw-feedback";
 
-// Use draw occlusion to skip draw quads when they are not shown on screen.
-const char kEnableDrawOcclusion[] = "enable-draw-occlusion";
-
 // Use SkiaRenderer instead of GLRenderer for direct rendering.
 const char kUseSkiaRenderer[] = "use-skia-renderer";
 

ui/base/ui_base_switches.h

@@ -31,7 +31,6 @@ UI_BASE_EXPORT extern const char kDisableCompositedAntialiasing[];
 UI_BASE_EXPORT extern const char kDisableDwmComposition[];
 UI_BASE_EXPORT extern const char kDisableTouchAdjustment[];
 UI_BASE_EXPORT extern const char kDisableTouchDragDrop[];
-UI_BASE_EXPORT extern const char kEnableDrawOcclusion[];
 UI_BASE_EXPORT extern const char kEnableTouchDragDrop[];
 UI_BASE_EXPORT extern const char kEnableTouchableAppContextMenu[];
 UI_BASE_EXPORT extern const char kForceHighContrast[];