feat: Enable pressure monitor in linux and for render process OS-20368 (#110)

memory_pressure: Enable pressure monitor in linux and for render process OS-20368

Signed-off-by: Tariq Bashir <[email protected]>

Author: t-bashir-bs

patches/chromium/.patches

@@ -195,4 +195,5 @@ add_switch_to_disable_font_matching_cache_os-14352.patch
 fix_overlay_strategy_for_html_pages_with_transparency_os-19250.patch
 feat_nexus-window_implement_setopacity_support_for_nexus_platform.patch
 ozone_nexus_implement_setfullscreen_for_nexuswindow_os-19899.patch
+enable_memory_pressure_monitoring_and_enable_for_renderer_process.patch
 fix_wayland_window_call_setwindowgeometry_for_position_updates.patch

patches/chromium/enable_memory_pressure_monitoring_and_enable_for_renderer_process.patch

@@ -0,0 +1,81 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Tariq Bashir <[email protected]>
+Date: Tue, 2 Dec 2025 16:01:17 +0000
+Subject: Enable memory pressure monitoring and enable for renderer process
+ OS-20368
+
+Chromium has disabled memory pressure monitoring for Linux by default
+(https://chromium-review.googlesource.com/c/chromium/src/+/2792266). This patch
+re-enables it and also cherry picks the QtWebEngine patch that enables memory pressure
+monitoring for the Linux renderer processes from:
+https://cam-gerrit.brightsign.info/c/qtwebengine-chromium/+/15831
+
+diff --git a/components/memory_pressure/system_memory_pressure_evaluator.cc b/components/memory_pressure/system_memory_pressure_evaluator.cc
+index 3299c7fab7899d8d18e590addb66a4cd1900adfe..3a74620122bb2bc4491c3b85b143b5a21ec0172d 100644
+--- a/components/memory_pressure/system_memory_pressure_evaluator.cc
++++ b/components/memory_pressure/system_memory_pressure_evaluator.cc
+@@ -17,6 +17,8 @@
+ #include "components/memory_pressure/system_memory_pressure_evaluator_mac.h"
+ #elif BUILDFLAG(IS_WIN)
+ #include "components/memory_pressure/system_memory_pressure_evaluator_win.h"
++#elif BUILDFLAG(IS_LINUX)
++#include "components/memory_pressure/system_memory_pressure_evaluator_linux.h"
+ #endif
+ 
+ namespace memory_pressure {
+@@ -51,6 +53,9 @@ SystemMemoryPressureEvaluator::CreateDefaultSystemEvaluator(
+     evaluator->CreateOSSignalPressureEvaluator(monitor->CreateVoter());
+   }
+   return evaluator;
++#elif BUILDFLAG(IS_LINUX)
++  return std::make_unique<memory_pressure::os_linux::SystemMemoryPressureEvaluator>(
++      monitor->CreateVoter());
+ #else
+   // Chrome OS and Chromecast evaluators are created in separate components.
+   return nullptr;
+diff --git a/content/renderer/render_thread_impl.cc b/content/renderer/render_thread_impl.cc
+index 7b4fb3da23f4e7805f74932cd959229554c3e217..c65b533af1f980bcb2c17d9df5196255b30165ed 100644
+--- a/content/renderer/render_thread_impl.cc
++++ b/content/renderer/render_thread_impl.cc
+@@ -63,6 +63,7 @@
+ #include "cc/trees/raster_context_provider_wrapper.h"
+ #include "cc/trees/ukm_manager.h"
+ #include "components/discardable_memory/client/client_discardable_shared_memory_manager.h"
++#include "components/memory_pressure/multi_source_memory_pressure_monitor.h"
+ #include "components/metrics/public/mojom/single_sample_metrics.mojom.h"
+ #include "components/metrics/single_sample_metrics.h"
+ #include "components/viz/common/features.h"
+@@ -634,6 +635,9 @@ void RenderThreadImpl::Init() {
+   // been initialized by the Zygote before this instance became a Renderer.
+   media::InitializeMediaLibrary();
+ 
++  memory_pressure_monitor_ = std::make_unique<memory_pressure::MultiSourceMemoryPressureMonitor>();
++  memory_pressure_monitor_->MaybeStartPlatformVoter();
++
+   memory_pressure_listener_ = std::make_unique<base::MemoryPressureListener>(
+       FROM_HERE,
+       base::BindRepeating(&RenderThreadImpl::OnMemoryPressure,
+diff --git a/content/renderer/render_thread_impl.h b/content/renderer/render_thread_impl.h
+index 351210e73bde2da89645ad6c09e5c4820d2321b5..8d6f914ac2d499b78187b3c9216a50c02cf66034 100644
+--- a/content/renderer/render_thread_impl.h
++++ b/content/renderer/render_thread_impl.h
+@@ -86,6 +86,10 @@ namespace media {
+ class GpuVideoAcceleratorFactories;
+ }
+ 
++namespace memory_pressure {
++class MultiSourceMemoryPressureMonitor;
++}
++
+ namespace mojo {
+ class BinderMap;
+ }
+@@ -543,6 +547,8 @@ class CONTENT_EXPORT RenderThreadImpl
+ 
+   HistogramCustomizer histogram_customizer_;
+ 
++  std::unique_ptr<memory_pressure::MultiSourceMemoryPressureMonitor> memory_pressure_monitor_;
++
+   std::unique_ptr<base::MemoryPressureListener> memory_pressure_listener_;
+ 
+   std::unique_ptr<viz::Gpu> gpu_;