From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: deepak1556 <hop2deep@gmail.com>
Date: Mon, 18 May 2020 11:12:26 -0700
Subject: allow disabling blink scheduler throttling per RenderView

This allows us to disable throttling for hidden windows.

diff --git a/content/browser/renderer_host/navigation_controller_impl_unittest.cc b/content/browser/renderer_host/navigation_controller_impl_unittest.cc
index 32b77897ef3669727fe05a1f3603a5f8335ec3cf..f1948d352bd71da5ec17d734e343bfd656d7ed69 100644
--- a/content/browser/renderer_host/navigation_controller_impl_unittest.cc
+++ b/content/browser/renderer_host/navigation_controller_impl_unittest.cc
@@ -163,6 +163,12 @@ class MockPageBroadcast : public blink::mojom::PageBroadcast {
               (network::mojom::AttributionSupport support),
               (override));
 
+  MOCK_METHOD(
+      void,
+      SetSchedulerThrottling,
+      (bool allowed),
+      (override));
+
   mojo::PendingAssociatedRemote<blink::mojom::PageBroadcast> GetRemote() {
     return receiver_.BindNewEndpointAndPassDedicatedRemote();
   }
diff --git a/content/browser/renderer_host/render_view_host_impl.cc b/content/browser/renderer_host/render_view_host_impl.cc
index 57926e0d557fdb3e8f46a096e335ecb5d1d2e13f..b0438d6077a3323785175424a3701ba4ae5e523d 100644
--- a/content/browser/renderer_host/render_view_host_impl.cc
+++ b/content/browser/renderer_host/render_view_host_impl.cc
@@ -714,6 +714,11 @@ void RenderViewHostImpl::SetBackgroundOpaque(bool opaque) {
   GetWidget()->GetAssociatedFrameWidget()->SetBackgroundOpaque(opaque);
 }
 
+void RenderViewHostImpl::SetSchedulerThrottling(bool allowed) {
+  if (auto& broadcast = GetAssociatedPageBroadcast())
+    broadcast->SetSchedulerThrottling(allowed);
+}
+
 bool RenderViewHostImpl::IsMainFrameActive() {
   return is_active();
 }
diff --git a/content/browser/renderer_host/render_view_host_impl.h b/content/browser/renderer_host/render_view_host_impl.h
index a94977d7a76ae9952bbba0efe59a7cb5021a1c84..11c4f890eaeae1329ca5a6634a698aef7a288fb4 100644
--- a/content/browser/renderer_host/render_view_host_impl.h
+++ b/content/browser/renderer_host/render_view_host_impl.h
@@ -139,6 +139,7 @@ class CONTENT_EXPORT RenderViewHostImpl
   void EnablePreferredSizeMode() override;
   void WriteIntoTrace(perfetto::TracedProto<TraceProto> context) const override;
 
+  void SetSchedulerThrottling(bool allowed) override;
   void SendWebPreferencesToRenderer();
   void SendRendererPreferencesToRenderer(
       const blink::RendererPreferences& preferences);
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.cc b/content/browser/renderer_host/render_widget_host_view_aura.cc
index cb9b21a3d3e99558e6892e00e73e550f68571daf..f18a3d6b4287d986c31db3385541cd20db68ecd5 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.cc
+++ b/content/browser/renderer_host/render_widget_host_view_aura.cc
@@ -553,8 +553,8 @@ void RenderWidgetHostViewAura::ShowImpl(PageVisibilityState page_visibility) {
   // OnShowWithPageVisibility will not call NotifyHostAndDelegateOnWasShown,
   // which updates `visibility_`, unless the host is hidden. Make sure no update
   // is needed.
-  DCHECK(host_->is_hidden() || visibility_ == Visibility::VISIBLE);
-  OnShowWithPageVisibility(page_visibility);
+  if (host_->is_hidden() || visibility_ == Visibility::VISIBLE)
+    OnShowWithPageVisibility(page_visibility);
 }
 
 void RenderWidgetHostViewAura::NotifyHostAndDelegateOnWasShown(
diff --git a/content/public/browser/render_view_host.h b/content/public/browser/render_view_host.h
index 20ca763ff7f55e8176b77349b41917b11e051ae6..a50c122064b5f0092f57e3d508fb19389b72203b 100644
--- a/content/public/browser/render_view_host.h
+++ b/content/public/browser/render_view_host.h
@@ -75,6 +75,9 @@ class CONTENT_EXPORT RenderViewHost {
   virtual void WriteIntoTrace(
       perfetto::TracedProto<TraceProto> context) const = 0;
 
+  // Disable/Enable scheduler throttling.
+  virtual void SetSchedulerThrottling(bool allowed) {}
+
  private:
   // This interface should only be implemented inside content.
   friend class RenderViewHostImpl;
diff --git a/content/test/test_page_broadcast.h b/content/test/test_page_broadcast.h
index 603798ae0d45836f1bf3e6608761ce1467303310..2d8caa06e418f123d7565b96d40c66fb51617a6d 100644
--- a/content/test/test_page_broadcast.h
+++ b/content/test/test_page_broadcast.h
@@ -50,6 +50,7 @@ class TestPageBroadcast : public blink::mojom::PageBroadcast {
       network::mojom::AttributionSupport support) override;
   void UpdateColorProviders(
       const blink::ColorProviderColorMaps& color_provider_colors) override;
+  void SetSchedulerThrottling(bool allowed) override {}
 
   mojo::AssociatedReceiver<blink::mojom::PageBroadcast> receiver_;
 };
diff --git a/third_party/blink/public/mojom/page/page.mojom b/third_party/blink/public/mojom/page/page.mojom
index ed73a6fe6d146eac904f0aa0d88facf055df503e..4bbc792068db75739a7ceb8ad01c85f9d3bbd8f6 100644
--- a/third_party/blink/public/mojom/page/page.mojom
+++ b/third_party/blink/public/mojom/page/page.mojom
@@ -173,4 +173,7 @@ interface PageBroadcast {
   // 2. The ColorProvider associated with the WebContents changes as a result
   // of theme changes.
   UpdateColorProviders(ColorProviderColorMaps color_provider_colors);
+
+  // Whether to enable the Renderer scheduler background throttling.
+  SetSchedulerThrottling(bool allowed);
 };
diff --git a/third_party/blink/public/web/web_view.h b/third_party/blink/public/web/web_view.h
index c4348be90db209a757f21cbc518e1244fe0954d5..1ee953ad860291cdc1095880f6646d1d05732843 100644
--- a/third_party/blink/public/web/web_view.h
+++ b/third_party/blink/public/web/web_view.h
@@ -376,6 +376,7 @@ class BLINK_EXPORT WebView {
   // Scheduling -----------------------------------------------------------
 
   virtual PageScheduler* Scheduler() const = 0;
+  virtual void SetSchedulerThrottling(bool allowed) {}
 
   // Visibility -----------------------------------------------------------
 
diff --git a/third_party/blink/renderer/core/exported/web_view_impl.cc b/third_party/blink/renderer/core/exported/web_view_impl.cc
index fb042e637c831e3de72d7ed6fd33db9df5976c18..689010902c8508b85208618cc11b922adf10c08e 100644
--- a/third_party/blink/renderer/core/exported/web_view_impl.cc
+++ b/third_party/blink/renderer/core/exported/web_view_impl.cc
@@ -2431,6 +2431,10 @@ void WebViewImpl::SetPageLifecycleStateInternal(
   TRACE_EVENT2("navigation", "WebViewImpl::SetPageLifecycleStateInternal",
                "old_state", old_state, "new_state", new_state);
 
+  // If backgroundThrottling is disabled, the page is always visible.
+  if (!scheduler_throttling_allowed_)
+      new_state->visibility = mojom::blink::PageVisibilityState::kVisible;
+
   bool storing_in_bfcache = new_state->is_in_back_forward_cache &&
                             !old_state->is_in_back_forward_cache;
   bool restoring_from_bfcache = !new_state->is_in_back_forward_cache &&
@@ -3937,10 +3941,23 @@ PageScheduler* WebViewImpl::Scheduler() const {
   return GetPage()->GetPageScheduler();
 }
 
+void WebViewImpl::SetSchedulerThrottling(bool allowed) {
+  DCHECK(GetPage());
+  scheduler_throttling_allowed_ = allowed;
+  GetPage()->GetPageScheduler()->SetPageVisible(!allowed || GetVisibilityState() == mojom::blink::PageVisibilityState::kVisible);
+}
+
 void WebViewImpl::SetVisibilityState(
     mojom::blink::PageVisibilityState visibility_state,
     bool is_initial_state) {
   DCHECK(GetPage());
+
+  if (!scheduler_throttling_allowed_) {
+    GetPage()->SetVisibilityState(mojom::blink::PageVisibilityState::kVisible, is_initial_state);
+    GetPage()->GetPageScheduler()->SetPageVisible(true);
+    return;
+  }
+
   GetPage()->SetVisibilityState(visibility_state, is_initial_state);
   // Do not throttle if the page should be painting.
   bool is_visible =
diff --git a/third_party/blink/renderer/core/exported/web_view_impl.h b/third_party/blink/renderer/core/exported/web_view_impl.h
index db7f1cb1b0f682a20a618b342a9a42add0db9e74..bc2c06fd0e7d02624ad97ab1ebe21ff7b2217c05 100644
--- a/third_party/blink/renderer/core/exported/web_view_impl.h
+++ b/third_party/blink/renderer/core/exported/web_view_impl.h
@@ -451,6 +451,7 @@ class CORE_EXPORT WebViewImpl final : public WebView,
   LocalDOMWindow* PagePopupWindow() const;
 
   PageScheduler* Scheduler() const override;
+  void SetSchedulerThrottling(bool allowed) override;
   void SetVisibilityState(mojom::blink::PageVisibilityState visibility_state,
                           bool is_initial_state) override;
   mojom::blink::PageVisibilityState GetVisibilityState() override;
@@ -925,6 +926,8 @@ class CORE_EXPORT WebViewImpl final : public WebView,
   // If true, we send IPC messages when |preferred_size_| changes.
   bool send_preferred_size_changes_ = false;
 
+  bool scheduler_throttling_allowed_ = true;
+
   // Whether the preferred size may have changed and |UpdatePreferredSize| needs
   // to be called.
   bool needs_preferred_size_update_ = true;
