Add a flag for for controlling Canvas resource when its in background

Adding a flag to control canvas resource management: when it's enabled, the canvas context frees its resource to save memory when it's running in the background; and it restores its resource when it is in focus again. Bug:1268146 Change-Id: Ie0e0094357412a73d0a2f96d953a474110153b58 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3268231 Commit-Queue: Yi Xu <yiyix@chromium.org> Reviewed-by: Daniel Cheng <dcheng@chromium.org> Reviewed-by: John Abd-El-Malek <jam@chromium.org> Reviewed-by: Juanmi Huertas <juanmihd@chromium.org> Reviewed-by: Fernando Serboncini <fserb@chromium.org> Cr-Commit-Position: refs/heads/main@{#940698}
FairyWorld · Nov 11, 2021 · bee4563 · bee4563
1 parent 10a610d
commit bee4563
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diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
@@ -6603,6 +6603,11 @@ const FeatureEntry kFeatureEntries[] = {
      flag_descriptions::kCanvas2DLayersDescription, kOsAll,
      SINGLE_VALUE_TYPE(switches::kEnableCanvas2DLayers)},
 
+    {"enable-canvas-context-lost-in-background",
+     flag_descriptions::kEnableCanvasContextLostInBackgroundName,
+     flag_descriptions::kEnableCanvasContextLostInBackgroundDescription, kOsAll,
+     SINGLE_VALUE_TYPE(switches::kEnableCanvasContextLostInBackground)},
+
     {"new-canvas-2d-api", flag_descriptions::kNewCanvas2DAPIName,
      flag_descriptions::kNewCanvas2DAPIDescription, kOsAll,
      SINGLE_VALUE_TYPE(switches::kEnableNewCanvas2DAPI)},

diff --git a/chrome/browser/flag-metadata.json b/chrome/browser/flag-metadata.json
@@ -1505,6 +1505,11 @@
     "owners": ["ydago"],
     "expiry_milestone": 99
   },
+  {
+    "name": "enable-canvas-context-lost-in-background",
+    "owners": [ "chrome-canvas@google.com" ],
+    "expiry_milestone": 100
+  },
   {
     "name": "enable-cascade-layers",
     "owners": [ "xiaochengh" ],

diff --git a/chrome/browser/flag_descriptions.cc b/chrome/browser/flag_descriptions.cc
@@ -998,6 +998,11 @@ const char kDownloadRangeName[] = "Enable download range support";
 const char kDownloadRangeDescription[] =
     "Enables arbitrary download range request support.";
 
+const char kEnableCanvasContextLostInBackgroundName[] =
+    "Enable canvas context to be lost in background";
+const char kEnableCanvasContextLostInBackgroundDescription[] =
+    "Enable canvas context to be cleared when it is running in background";
+
 const char kEnableLayoutNGName[] = "Enable LayoutNG";
 const char kEnableLayoutNGDescription[] =
     "Enable Blink's next generation layout engine.";

diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
@@ -630,6 +630,9 @@ extern const char kDownloadProgressMessageDescription[];
 extern const char kDownloadRangeName[];
 extern const char kDownloadRangeDescription[];
 
+extern const char kEnableCanvasContextLostInBackgroundName[];
+extern const char kEnableCanvasContextLostInBackgroundDescription[];
+
 extern const char kEnableFencedFramesName[];
 extern const char kEnableFencedFramesDescription[];
 

diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
@@ -2631,6 +2631,10 @@ const blink::web_pref::WebPreferences WebContentsImpl::ComputeWebPreferences() {
   prefs.canvas_2d_layers_enabled =
       command_line.HasSwitch(switches::kEnableCanvas2DLayers) ||
       base::FeatureList::IsEnabled(features::kEnableCanvas2DLayers);
+  prefs.canvas_context_lost_in_background_enabled =
+      command_line.HasSwitch(switches::kEnableCanvasContextLostInBackground) ||
+      base::FeatureList::IsEnabled(
+          features::kEnableCanvasContextLostInBackground);
   prefs.new_canvas_2d_api_enabled =
       command_line.HasSwitch(switches::kEnableNewCanvas2DAPI) ||
       base::FeatureList::IsEnabled(features::kEnableNewCanvas2DAPI);

diff --git a/content/public/common/content_features.cc b/content/public/common/content_features.cc
@@ -285,6 +285,10 @@ const base::Feature kEmbeddingRequiresOptIn{"EmbeddingRequiresOptIn",
 const base::Feature kEnableCanvas2DLayers{"EnableCanvas2DLayers",
                                           base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Enables canvas context to clear context when it's running in background.
+const base::Feature kEnableCanvasContextLostInBackground{
+    "EnableCanvasContextLostInBackground", base::FEATURE_DISABLED_BY_DEFAULT};
+
 // Enables new canvas 2d api features. Enabled either with either
 // enable-experimental-canvas-features or new-canvas-2d-api runtime flags
 const base::Feature kEnableNewCanvas2DAPI{"EnableNewCanvas2DAPI",

diff --git a/content/public/common/content_features.h b/content/public/common/content_features.h
@@ -73,6 +73,7 @@ CONTENT_EXPORT extern const base::Feature kDocumentPolicyNegotiation;
 CONTENT_EXPORT extern const base::Feature kEarlyHintsPreloadForNavigation;
 CONTENT_EXPORT extern const base::Feature kEmbeddingRequiresOptIn;
 CONTENT_EXPORT extern const base::Feature kEnableCanvas2DLayers;
+CONTENT_EXPORT extern const base::Feature kEnableCanvasContextLostInBackground;
 CONTENT_EXPORT extern const base::Feature kEnableNewCanvas2DAPI;
 CONTENT_EXPORT extern const base::Feature kEnumerateDevicesHideDeviceIDs;
 CONTENT_EXPORT extern const base::Feature kExperimentalAccessibilityLabels;

diff --git a/content/public/common/content_switch_dependent_feature_overrides.cc b/content/public/common/content_switch_dependent_feature_overrides.cc
@@ -54,6 +54,9 @@ GetSwitchDependentFeatureOverrides(const base::CommandLine& command_line) {
       {switches::kEnableExperimentalWebPlatformFeatures,
        std::cref(features::kOriginIsolationHeader),
        base::FeatureList::OVERRIDE_ENABLE_FEATURE},
+      {switches::kEnableExperimentalWebPlatformFeatures,
+       std::cref(features::kEnableCanvasContextLostInBackground),
+       base::FeatureList::OVERRIDE_ENABLE_FEATURE},
       {switches::kEnableExperimentalWebPlatformFeatures,
        std::cref(features::kEnableNewCanvas2DAPI),
        base::FeatureList::OVERRIDE_ENABLE_FEATURE},

diff --git a/content/public/common/content_switches.cc b/content/public/common/content_switches.cc
@@ -90,6 +90,10 @@ const char kDisableAccelerated2dCanvas[]    = "disable-accelerated-2d-canvas";
 // Enable in-progress canvas 2d API methods BeginLayer and EndLayer.
 const char kEnableCanvas2DLayers[] = "canvas-2d-layers";
 
+// Enables canvas to clear its context when it is running in background.
+const char kEnableCanvasContextLostInBackground[] =
+    "enable-canvas-context-lost-in-background";
+
 // Enable in-progress canvas 2d API features.
 const char kEnableNewCanvas2DAPI[] = "new-canvas-2d-api";
 

diff --git a/content/public/common/content_switches.h b/content/public/common/content_switches.h
@@ -115,6 +115,7 @@ CONTENT_EXPORT extern const char kEnableLCDText[];
 CONTENT_EXPORT extern const char kEnableLogging[];
 CONTENT_EXPORT extern const char kEnableNetworkInformationDownlinkMax[];
 CONTENT_EXPORT extern const char kEnableCanvas2DLayers[];
+CONTENT_EXPORT extern const char kEnableCanvasContextLostInBackground[];
 CONTENT_EXPORT extern const char kEnableNewCanvas2DAPI[];
 CONTENT_EXPORT extern const char kDisableNv12DxgiVideo[];
 CONTENT_EXPORT extern const char kEnablePluginPlaceholderTesting[];

diff --git a/third_party/blink/common/web_preferences/web_preferences_mojom_traits.cc b/third_party/blink/common/web_preferences/web_preferences_mojom_traits.cc
@@ -101,6 +101,8 @@ bool StructTraits<blink::mojom::WebPreferencesDataView,
   out->accelerated_2d_canvas_enabled = data.accelerated_2d_canvas_enabled();
   out->new_canvas_2d_api_enabled = data.new_canvas_2d_api_enabled();
   out->canvas_2d_layers_enabled = data.canvas_2d_layers_enabled();
+  out->canvas_context_lost_in_background_enabled =
+      data.canvas_context_lost_in_background_enabled();
   out->antialiased_2d_canvas_disabled = data.antialiased_2d_canvas_disabled();
   out->antialiased_clips_2d_canvas_enabled =
       data.antialiased_clips_2d_canvas_enabled();

diff --git a/third_party/blink/public/common/web_preferences/web_preferences.h b/third_party/blink/public/common/web_preferences/web_preferences.h
@@ -98,6 +98,7 @@ struct BLINK_COMMON_EXPORT WebPreferences {
   bool hide_scrollbars;
   bool accelerated_2d_canvas_enabled;
   bool canvas_2d_layers_enabled = false;
+  bool canvas_context_lost_in_background_enabled = false;
   bool new_canvas_2d_api_enabled;
   bool antialiased_2d_canvas_disabled;
   bool antialiased_clips_2d_canvas_enabled;

diff --git a/third_party/blink/public/common/web_preferences/web_preferences_mojom_traits.h b/third_party/blink/public/common/web_preferences/web_preferences_mojom_traits.h
@@ -228,6 +228,11 @@ struct BLINK_COMMON_EXPORT StructTraits<blink::mojom::WebPreferencesDataView,
     return r.accelerated_2d_canvas_enabled;
   }
 
+  static bool canvas_context_lost_in_background_enabled(
+      const blink::web_pref::WebPreferences& r) {
+    return r.canvas_context_lost_in_background_enabled;
+  }
+
   static bool new_canvas_2d_api_enabled(
       const blink::web_pref::WebPreferences& r) {
     return r.new_canvas_2d_api_enabled;

diff --git a/third_party/blink/public/mojom/webpreferences/web_preferences.mojom b/third_party/blink/public/mojom/webpreferences/web_preferences.mojom
@@ -153,6 +153,7 @@ struct WebPreferences {
   bool webgl_errors_to_console_enabled;
   bool hide_scrollbars;
   bool accelerated_2d_canvas_enabled;
+  bool canvas_context_lost_in_background_enabled;
   bool new_canvas_2d_api_enabled;
   bool canvas_2d_layers_enabled;
   bool antialiased_2d_canvas_disabled;

diff --git a/third_party/blink/renderer/core/exported/web_view_impl.cc b/third_party/blink/renderer/core/exported/web_view_impl.cc
@@ -1486,6 +1486,10 @@ void WebView::ApplyWebPreferences(const web_pref::WebPreferences& prefs,
   RuntimeEnabledFeatures::SetAccelerated2dCanvasEnabled(
       prefs.accelerated_2d_canvas_enabled);
 
+  // Enable canvas to clear its context when it is running in background.
+  RuntimeEnabledFeatures::SetCanvasContextLostInBackgroundEnabled(
+      prefs.canvas_context_lost_in_background_enabled);
+
   // Enable new canvas 2d api features
   RuntimeEnabledFeatures::SetNewCanvas2DAPIEnabled(
       prefs.new_canvas_2d_api_enabled);

diff --git a/third_party/blink/renderer/platform/runtime_enabled_features.json5 b/third_party/blink/renderer/platform/runtime_enabled_features.json5
@@ -358,6 +358,9 @@
       name: "CanvasColorManagementV2",
       status: "experimental",
     },
+    {
+      name: "CanvasContextLostInBackground",
+    },
     {
       name: "CanvasFormattedText",
       status: "experimental",

diff --git a/tools/metrics/histograms/enums.xml b/tools/metrics/histograms/enums.xml
@@ -50663,6 +50663,7 @@ from previous Chrome versions.
   <int value="-446220201" label="EnableIncognitoShortcutOnDesktop:enabled"/>
   <int value="-444867364" label="Metal:enabled"/>
   <int value="-442352394" label="IframeOneGoogleBar:disabled"/>
+  <int value="-441508443" label="enable-canvas-context-lost-in-background"/>
   <int value="-438379844" label="SwapSideVolumeButtonsForOrientation:enabled"/>
   <int value="-436470115" label="TouchpadAndWheelScrollLatching:enabled"/>
   <int value="-435914745" label="ClipboardContentSetting:disabled"/>