OpenGL: Fix missing buffered image after context detach

Prior to this commit a Component with setBufferedToImage (true) could
have its image buffer deleted when an OpenGL context was detached. This
meant that this Component continued to be rendered without buffering
even though it was previously requested that it use a buffer.

Author: szarvas

modules/juce_gui_basics/detail/juce_ComponentHelpers.h

@@ -32,6 +32,8 @@
   ==============================================================================
 */
 
+#include "juce_ScalingHelpers.h"
+
 namespace juce::detail
 {
 

modules/juce_gui_basics/detail/juce_ScalingHelpers.h

@@ -32,6 +32,8 @@
   ==============================================================================
 */
 
+#pragma once
+
 namespace juce::detail
 {
 

modules/juce_opengl/opengl/juce_OpenGLContext.cpp

@@ -32,6 +32,8 @@
   ==============================================================================
 */
 
+#include <juce_gui_basics/detail/juce_ComponentHelpers.h>
+
 #if JUCE_MAC
  #include <juce_gui_basics/native/juce_PerScreenDisplayLinks_mac.h>
 #endif
@@ -1102,19 +1104,12 @@ class OpenGLContext::Attachment final : public ComponentMovementWatcher,
         detach();
     }
 
-    static void clearCachedImagesInComponentTree (Component& root)
-    {
-        root.setCachedComponentImage (nullptr);
-
-        for (auto* child : root.getChildren())
-            clearCachedImagesInComponentTree (*child);
-    }
-
     void detach()
     {
         auto& comp = *getComponent();
         stop();
-        clearCachedImagesInComponentTree (comp);
+        detail::ComponentHelpers::releaseAllCachedImageResources (comp);
+        comp.setCachedComponentImage (nullptr);
         context.nativeContext = nullptr;
     }