[blink] Stream scripts on preload

Start streaming ScriptResources when they are fetched, so that they
can start streaming during preload, before the script tag is seen.
This is enabled with a new ScriptStreamingOnPreload flag.

Bug: chromium:865098
Change-Id: I4a2874bce857a538f4bd35a818254ca9617f1a72
Reviewed-on: https://chromium-review.googlesource.com/c/1185185
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Hiroshige Hayashizaki <hiroshige@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610370}

content/child/runtime_features.cc

@@ -413,6 +413,9 @@ void SetRuntimeFeaturesDefaultsAndUpdateFromArgs(
   WebRuntimeFeatures::EnableScheduledScriptStreaming(
       base::FeatureList::IsEnabled(features::kScheduledScriptStreaming));
 
+  WebRuntimeFeatures::EnableScriptStreamingOnPreload(
+      base::FeatureList::IsEnabled(features::kScriptStreamingOnPreload));
+
   WebRuntimeFeatures::EnableMergeBlockingNonBlockingPools(
       base::FeatureList::IsEnabled(base::kMergeBlockingNonBlockingPools));
 

content/public/common/content_features.cc

@@ -620,6 +620,10 @@ const base::Feature kWorkStealingInScriptRunner{
 const base::Feature kScheduledScriptStreaming{
     "ScheduledScriptStreaming", base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Start streaming scripts on script preload.
+const base::Feature kScriptStreamingOnPreload{
+    "ScriptStreamingOnPreload", base::FEATURE_DISABLED_BY_DEFAULT};
+
 #if defined(OS_ANDROID)
 // Autofill Accessibility in Android.
 // crbug.com/627860

content/public/common/content_features.h

@@ -138,6 +138,7 @@ CONTENT_EXPORT extern const base::Feature kWebXrOrientationSensorDevice;
 CONTENT_EXPORT extern const base::Feature kWipeCorruptV2IDBDatabases;
 CONTENT_EXPORT extern const base::Feature kWorkStealingInScriptRunner;
 CONTENT_EXPORT extern const base::Feature kScheduledScriptStreaming;
+CONTENT_EXPORT extern const base::Feature kScriptStreamingOnPreload;
 
 #if defined(OS_ANDROID)
 CONTENT_EXPORT extern const base::Feature kAndroidAutofillAccessibility;

third_party/WebKit/LayoutTests/SlowTests

@@ -356,6 +356,8 @@ crbug.com/826957 fast/peerconnection/RTCPeerConnection-manyCandidates.html [ Slo
 crbug.com/842995 external/wpt/html/semantics/scripting-1/the-script-element/execution-timing/078.html [ Slow ]
 crbug.com/626703 external/wpt/html/semantics/scripting-1/the-script-element/async_007.htm [ Slow ]
 crbug.com/626703 external/wpt/html/semantics/scripting-1/the-script-element/async_010.htm [ Slow ]
+crbug.com/626703 virtual/streaming-preload/external/wpt/html/semantics/scripting-1/the-script-element/async_007.htm [ Slow ]
+crbug.com/626703 virtual/streaming-preload/external/wpt/html/semantics/scripting-1/the-script-element/async_010.htm [ Slow ]
 
 crbug.com/840792 [ Mac10.12 Mac10.13 ] external/wpt/pointerevents/pointerevent_touch-action-table-test_touch-manual.html [ Slow ]
 

third_party/WebKit/LayoutTests/TestExpectations

@@ -3312,6 +3312,8 @@ crbug.com/626703 external/wpt/websockets/Create-Secure-extensions-empty.any.html
 crbug.com/626703 external/wpt/websockets/Create-Secure-extensions-empty.any.worker.html [ Timeout ]
 crbug.com/626703 external/wpt/html/semantics/scripting-1/the-script-element/module/dynamic-import/string-compilation-integrity-classic.sub.html [ Skip ]
 crbug.com/626703 external/wpt/html/semantics/scripting-1/the-script-element/module/dynamic-import/string-compilation-integrity-module.sub.html [ Skip ]
+crbug.com/626703 virtual/streaming-preload/external/wpt/html/semantics/scripting-1/the-script-element/module/dynamic-import/string-compilation-integrity-classic.sub.html [ Skip ]
+crbug.com/626703 virtual/streaming-preload/external/wpt/html/semantics/scripting-1/the-script-element/module/dynamic-import/string-compilation-integrity-module.sub.html [ Skip ]
 crbug.com/626703 external/wpt/html/browsers/history/joint-session-history/joint-session-history-remove-iframe.html [ Timeout ]
 crbug.com/626703 external/wpt/css/vendor-imports/mozilla/mozilla-central-reftests/flexbox/flexbox-flex-basis-content-003a.html [ Failure ]
 crbug.com/626703 external/wpt/css/vendor-imports/mozilla/mozilla-central-reftests/flexbox/flexbox-flex-basis-content-004a.html [ Failure ]
@@ -4263,6 +4265,7 @@ crbug.com/734762 inspector-protocol/timeline/page-frames.js [ Failure Pass ]
 
 # module script lacks XHTML support
 crbug.com/717643 external/wpt/html/semantics/scripting-1/the-script-element/module/module-in-xhtml.xhtml [ Failure ]
+crbug.com/717643 virtual/streaming-preload/external/wpt/html/semantics/scripting-1/the-script-element/module/module-in-xhtml.xhtml [ Failure ]
 
 # known bug: import() inside set{Timeout,Interval}
 
@@ -4271,6 +4274,10 @@ crbug.com/796034 external/wpt/html/semantics/scripting-1/the-script-element/modu
 crbug.com/796034 external/wpt/html/semantics/scripting-1/the-script-element/module/dynamic-import/string-compilation-base-url-external-module.html [ Failure ]
 crbug.com/796034 external/wpt/html/semantics/scripting-1/the-script-element/module/dynamic-import/string-compilation-base-url-inline-classic.html [ Failure ]
 crbug.com/796034 external/wpt/html/semantics/scripting-1/the-script-element/module/dynamic-import/string-compilation-base-url-inline-module.html [ Failure ]
+crbug.com/796034 virtual/streaming-preload/external/wpt/html/semantics/scripting-1/the-script-element/module/dynamic-import/string-compilation-base-url-external-classic.html [ Failure ]
+crbug.com/796034 virtual/streaming-preload/external/wpt/html/semantics/scripting-1/the-script-element/module/dynamic-import/string-compilation-base-url-external-module.html [ Failure ]
+crbug.com/796034 virtual/streaming-preload/external/wpt/html/semantics/scripting-1/the-script-element/module/dynamic-import/string-compilation-base-url-inline-classic.html [ Failure ]
+crbug.com/796034 virtual/streaming-preload/external/wpt/html/semantics/scripting-1/the-script-element/module/dynamic-import/string-compilation-base-url-inline-module.html [ Failure ]
 
 # Geolocation tests
 crbug.com/745079 external/wpt/geolocation-API/PositionOptions.https.html [ Failure ]

third_party/WebKit/LayoutTests/VirtualTestSuites

@@ -1026,5 +1026,15 @@
     "prefix": "transferable-streams",
     "base": "http/tests/streams/transferable",
     "args": ["--enable-blink-features=TransferableStreams"]
+  },
+  {
+    "prefix": "streaming-preload",
+    "base": "http/tests/fetch",
+    "args": ["--enable-features=ScriptStreamingOnPreload"]
+  },
+  {
+    "prefix": "streaming-preload",
+    "base": "external/wpt/html/semantics/scripting-1",
+    "args": ["--enable-features=ScriptStreamingOnPreload"]
   }
 ]

third_party/WebKit/LayoutTests/virtual/streaming-preload/external/wpt/html/semantics/scripting-1/README.txt

+# This suite runs the tests in external/wpt/html/semantics/scripting-1 with the
+# flag --enable-feature=ScriptStreamingOnPreload
\ No newline at end of file

third_party/WebKit/LayoutTests/virtual/streaming-preload/http/tests/fetch/README.txt

+# This suite runs the tests in http/tests/fetch with the flag
+# --enable-feature=ScriptStreamingOnPreload
\ No newline at end of file

third_party/blink/public/platform/web_runtime_features.h

@@ -206,6 +206,7 @@ class WebRuntimeFeatures {
   BLINK_PLATFORM_EXPORT static void EnableAutomationControlled(bool);
   BLINK_PLATFORM_EXPORT static void EnableWorkStealingInScriptRunner(bool);
   BLINK_PLATFORM_EXPORT static void EnableScheduledScriptStreaming(bool);
+  BLINK_PLATFORM_EXPORT static void EnableScriptStreamingOnPreload(bool);
   BLINK_PLATFORM_EXPORT static void EnableExperimentalProductivityFeatures(
       bool);
   BLINK_PLATFORM_EXPORT static void EnableAutoplayIgnoresWebAudio(bool);

third_party/blink/renderer/core/loader/resource/script_resource.cc

@@ -42,6 +42,7 @@
 #include "third_party/blink/renderer/platform/loader/fetch/text_resource_decoder_options.h"
 #include "third_party/blink/renderer/platform/loader/subresource_integrity.h"
 #include "third_party/blink/renderer/platform/network/mime/mime_type_registry.h"
+#include "third_party/blink/renderer/platform/runtime_enabled_features.h"
 #include "third_party/blink/renderer/platform/shared_buffer.h"
 
 namespace blink {
@@ -80,7 +81,12 @@ ScriptResource* ScriptResource::Fetch(FetchParameters& params,
   ScriptResource* resource = ToScriptResource(
       fetcher->RequestResource(params, ScriptResourceFactory(), client));
 
-  if (streaming_allowed != kAllowStreaming) {
+  if (streaming_allowed == kAllowStreaming) {
+    // Start streaming the script as soon as we get it.
+    if (RuntimeEnabledFeatures::ScriptStreamingOnPreloadEnabled()) {
+      resource->StartStreaming(fetcher->Context().GetLoadingTaskRunner());
+    }
+  } else {
     // Advance the |streaming_state_| to kStreamingNotAllowed by calling
     // SetClientIsWaitingForFinished unless it is explicitly allowed.'
     //

third_party/blink/renderer/platform/exported/web_runtime_features.cc

@@ -552,6 +552,10 @@ void WebRuntimeFeatures::EnableScheduledScriptStreaming(bool enable) {
   RuntimeEnabledFeatures::SetScheduledScriptStreamingEnabled(enable);
 }
 
+void WebRuntimeFeatures::EnableScriptStreamingOnPreload(bool enable) {
+  RuntimeEnabledFeatures::SetScriptStreamingOnPreloadEnabled(enable);
+}
+
 void WebRuntimeFeatures::EnableExperimentalProductivityFeatures(bool enable) {
   RuntimeEnabledFeatures::SetExperimentalProductivityFeaturesEnabled(enable);
 }

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -1097,6 +1097,9 @@
       name: "ScriptedSpeechSynthesis",
       status: "stable",
     },
+    {
+      name: "ScriptStreamingOnPreload",
+    },
     // Serialize and restore scroll anchors.
     {
       name: "ScrollAnchorSerialization",