[Skia] Purge caches on memory pressure

https://bugs.webkit.org/show_bug.cgi?id=270634

Reviewed by Carlos Garcia Campos.

* Source/WebCore/PlatformWPE.cmake:
* Source/WebCore/page/MemoryRelease.cpp:
* Source/WebCore/page/skia/MemoryReleaseSkia.cpp: Added.
(WebCore::platformReleaseMemory):

Canonical link: https://commits.webkit.org/275967@main

Source/WebCore/page/MemoryRelease.cpp

@@ -253,7 +253,9 @@ void logMemoryStatistics(LogMemoryStatisticsReason reason)
 #endif
 
 #if !PLATFORM(COCOA)
+#if !USE(SKIA)
 void platformReleaseMemory(Critical) { }
+#endif
 void platformReleaseGraphicsMemory(Critical) { }
 void jettisonExpensiveObjectsOnTopLevelNavigation() { }
 void registerMemoryReleaseNotifyCallbacks() { }

Source/WebCore/page/skia/MemoryReleaseSkia.cpp

@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2024 Igalia S.L
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public License
+ * along with this library; see the file COPYING.LIB.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include "config.h"
+#include "MemoryRelease.h"
+
+#include <skia/core/SkGraphics.h>
+
+namespace WebCore {
+
+void platformReleaseMemory(Critical)
+{
+    SkGraphics::PurgeAllCaches();
+}
+
+} // namespace WebCore

Source/WebCore/platform/SourcesSkia.txt

@@ -21,6 +21,8 @@
 // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 // THE POSSIBILITY OF SUCH DAMAGE.
 
+page/skia/MemoryReleaseSkia.cpp
+
 platform/graphics/skia/TransformationMatrixSkia.cpp
 platform/graphics/skia/ColorSkia.cpp
 platform/graphics/skia/ComplexTextControllerSkia.cpp