From 74db060beb01129967ccd573b5493dfb0a31ad4e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Emilio=20Cobos=20=C3=81lvarez?= <emilio@crisal.io>
Date: Tue, 30 Mar 2021 00:05:14 +0000
Subject: [PATCH] Bug 1701807 - Partially revert the regressing bug for now,
 gotta find something smarter to do.

Differential Revision: https://phabricator.services.mozilla.com/D110180
---
 layout/base/PresShell.cpp                | 28 +-----------------------
 layout/base/PresShell.h                  |  4 ----
 modules/libpref/init/StaticPrefList.yaml | 25 ---------------------
 3 files changed, 1 insertion(+), 56 deletions(-)

diff --git a/layout/base/PresShell.cpp b/layout/base/PresShell.cpp
index aaaee87b130b..87449919637f 100644
--- a/layout/base/PresShell.cpp
+++ b/layout/base/PresShell.cpp
@@ -1822,14 +1822,10 @@ void PresShell::InitPaintSuppressionTimer() {
   int32_t delay = inProcess
                       ? StaticPrefs::nglayout_initialpaint_delay()
                       : StaticPrefs::nglayout_initialpaint_delay_in_oopif();
-  if (mPaintSuppressionAttempts) {
-    delay += mPaintSuppressionAttempts *
-             StaticPrefs::nglayout_initialpaint_retry_extra_delay();
-  }
   mPaintSuppressionTimer->InitWithNamedFuncCallback(
       [](nsITimer* aTimer, void* aPresShell) {
         RefPtr<PresShell> self = static_cast<PresShell*>(aPresShell);
-        self->UnsuppressPaintingFromTimer();
+        self->UnsuppressPainting();
       },
       this, delay, nsITimer::TYPE_ONE_SHOT,
       "PresShell::sPaintSuppressionCallback");
@@ -3912,28 +3908,6 @@ void PresShell::CancelPaintSuppressionTimer() {
   }
 }
 
-void PresShell::UnsuppressPaintingFromTimer() {
-  if (mIsDocumentGone || !mPaintingSuppressed) {
-    CancelPaintSuppressionTimer();
-    return;
-  }
-  if (!StaticPrefs::nglayout_initialpaint_unsuppress_with_no_background()) {
-    if (mPresContext->IsRootContentDocumentCrossProcess()) {
-      UpdateCanvasBackground();
-      if (!mHasCSSBackgroundColor) {
-        // We don't unsuppress painting if the page has a transparent
-        // background, as that usually means that the page is unstyled.
-        if (mPaintSuppressionAttempts++ <
-            StaticPrefs::nglayout_initialpaint_retry_max_retry_count()) {
-          InitPaintSuppressionTimer();
-          return;
-        }
-      }
-    }
-  }
-  UnsuppressPainting();
-}
-
 void PresShell::UnsuppressPainting() {
   CancelPaintSuppressionTimer();
 
diff --git a/layout/base/PresShell.h b/layout/base/PresShell.h
index e04004212f33..3766de592089 100644
--- a/layout/base/PresShell.h
+++ b/layout/base/PresShell.h
@@ -680,7 +680,6 @@ class PresShell final : public nsStubDocumentObserver,
   bool IsPaintingSuppressed() const { return mPaintingSuppressed; }
 
   void UnsuppressPainting();
-  void UnsuppressPaintingFromTimer();
   void InitPaintSuppressionTimer();
   void CancelPaintSuppressionTimer();
 
@@ -2989,9 +2988,6 @@ class PresShell final : public nsStubDocumentObserver,
   // re-use old pixels.
   RenderingStateFlags mRenderingStateFlags;
 
-  // The amount of times that we have tried to unsuppress painting off a timer.
-  int32_t mPaintSuppressionAttempts = 0;
-
   // Whether we're currently under a FlushPendingNotifications.
   // This is used to handle flush reentry correctly.
   // NOTE: This can't be a bitfield since AutoRestore has a reference to this
diff --git a/modules/libpref/init/StaticPrefList.yaml b/modules/libpref/init/StaticPrefList.yaml
index c10fd39423ca..313155116cd4 100644
--- a/modules/libpref/init/StaticPrefList.yaml
+++ b/modules/libpref/init/StaticPrefList.yaml
@@ -9325,31 +9325,6 @@
   value: 5
   mirror: always
 
-# Whether we should unsuppress painting from the initial paint timer when
-# there's no CSS background specified on the page.
-- name: nglayout.initialpaint.unsuppress_with_no_background
-  type: bool
-  value: false
-  mirror: always
-
-# If we retried, what is the extra delay we should use.
-# Note that this increment is multiplied for the current retry number.
-- name: nglayout.initialpaint.retry.extra_delay
-  type: int32_t
-  # Somewhat arbitrary, but not too high so as to miss lots of frames if the
-  # page begins to get styled. Note that we forcefully unsuppress when the load
-  # event arrives too, or on max retries, so this won't block painting if the
-  # page has loaded.
-  value: 25
-  mirror: always
-
-- name: nglayout.initialpaint.retry.max_retry_count
-  type: int32_t
-  # This gives us 5 + 30 + 55 + ... 380 == 2705ms before forcibly
-  # unsuppressing, which seems plenty.
-  value: 15
-  mirror: always
-
 #---------------------------------------------------------------------------
 # Prefs starting with "page_load."
 #---------------------------------------------------------------------------